Hubspot Emails Going to Spam? Causes & Fixes: Step-by-Step

Introduction

Most users complain that deliverability often drops after switching to HubSpot.

Open rates fall, replies slow down, and emails that used to land in the inbox start going to spam, especially in Outlook. In many cases, the same email sent directly from Gmail or Outlook reaches the inbox, but sent through HubSpot, it doesn’t.

This isn’t just a HubSpot issue. The entire email ecosystem tightened between 2024 and 2026.

Google and Yahoo introduced stricter requirements for bulk senders, SPF, DKIM, DMARC, one-click unsubscribe, and tight spam complaint thresholds. Microsoft followed with similar rules and went a step further by rejecting non-compliant emails outright instead of quietly sending them to spam. 

Spam still counts as “delivered.” Rejection means your email never lands in the inbox. 

The impact is already visible as the inbox placement has dropped across providers, with Outlook seeing some of the steepest declines. At the same time, most teams still rely on delivery rates instead of actual inbox placement, which hides the real problem.

So when emails start underperforming in HubSpot, the usual fixes, SPF, DKIM, list cleaning, rewriting copy, only go so far. They address parts of the problem, but not the structure behind it.

HubSpot does not send all emails the same way.

Marketing emails (campaigns, newsletters, workflows) go through HubSpot’s own infrastructure. Sales emails (sequences, 1:1 messages) go through your connected Google Workspace or Microsoft 365 inbox.

Different infrastructure means different reputation systems, different spam triggers, and different fixes. If you don’t separate the two, you end up fixing the wrong thing and the emails keep going to spam.

This guide breaks down both paths, shows how to identify which one is causing the issue, and walks through the exact fixes for each.

Why Do HubSpot Emails Go to Spam?

Inbox providers don’t care that you’re using HubSpot. Google, Microsoft, and Yahoo evaluate every email the same way before deciding where it lands, inbox, promotions, or spam.

They look at three things:

1. Sender reputation

Sender reputation is based on how recipients interact with your emails over time.

• Positive signals: replies, opens, moving emails out of spam
• Negative signals: spam complaints, deletes without reading, bounces

Reputation is tied to your sending domain and IP address. If either has a poor history, your emails will be filtered, regardless of the content.

2. Authentication setup

Inbox providers check if your email is properly verified using SPF, DKIM, and DMARC.

• If these are correctly set up and aligned, your emails are trusted more
• If they’re missing or broken, your emails look suspicious

Authentication doesn’t guarantee inbox placement, but without it, you’re very likely to land in spam.

3. Email content and structure

This is about what’s inside the email.

• Too many links, heavy HTML, or tracking elements can raise flags
• Poor text-to-image ratio or “spammy” formatting can hurt placement

Content issues usually affect individual emails, not your overall reputation but they still impact where each message lands.

In HubSpot, there are two different sending systems, and each one has its own reputation, its own risks, and its own fix. If you don’t identify which one you’re using, you end up fixing the wrong problem and nothing improves.

Which HubSpot Sending Path Are Your Emails On?

HubSpot looks like one platform, but it sends emails through two completely different systems. If you don’t know which one you’re using, you’ll fix the wrong problem.

Path 1: Marketing Hub (HubSpot’s network)

This includes newsletters, campaigns, workflows, and transactional emails.

• Emails are sent from HubSpot’s shared IP pool (or a dedicated IP if you have one)
• Your deliverability depends partly on other HubSpot users sharing that IP
• You don’t control the sending infrastructure directly

Path 2: Sales Hub (your inbox)

This includes 1:1 emails, sequences, and connected inbox conversations.

• Emails are sent from your Google Workspace or Microsoft 365 mailbox
• HubSpot is only the sending interface not the sender
• Gmail and Outlook evaluate these emails as if you sent them manually

If you’re using Marketing Hub, your emails are judged based on:

• HubSpot’s IP reputation
• Your domain authentication
• Your list quality

If you’re using Sales Hub, your emails are judged based on:

• Your mailbox reputation
• How warmed up your inbox is
• How recipients interact with your emails

That’s why the same email can land in:

• Inbox when sent manually from Gmail
• Spam when sent via HubSpot sequence

How Do You Diagnose Which Path Is Causing Spam?

Before you change the DNS records, content, or sending volume, you need to identify which sending system is actually causing the problem.

This is where most teams assume all HubSpot emails behave the same way, apply generic fixes, and see no improvement. In reality, Marketing Hub and Sales Hub are evaluated by completely different systems. If you don’t isolate the source, you’ll end up troubleshooting the wrong layer.

There are two key things to keep in mind during diagnosis:

• Delivery ≠ inbox placement: HubSpot may show emails as “delivered,” but they can still be landing in spam or promotions
• Each path has its own reputation: HubSpot’s IP reputation for Marketing emails vs your mailbox reputation for Sales emails

Once you understand that, identify which path your emails are using and validate where they actually land.

Quick Diagnostic Checklist

Use this to pinpoint the issue in a few minutes:

1. What type of emails are you sending?

• Newsletters, campaigns, workflows → Marketing Hub path
• Sequences, 1:1 emails, CRM sends → Sales Hub path

2. What system is actually sending the email?

• Sent through HubSpot infrastructure → Marketing Hub
• Sent through your connected Gmail or Outlook inbox → Sales Hub

3. Run a simple controlled test

Take the same email and send it two ways:

• Directly from your Gmail or Outlook inbox
• Through HubSpot (sequence or campaign)

What this tells you:

• Inbox when sent manually, spam via HubSpot → infrastructure issue
  
  • Sales Hub: mailbox reputation or tracking
  • Marketing Hub: shared IP reputation
• Spam in both cases → domain reputation or content issue

4. Check actual inbox placement (not just “delivered”)

An email marked “delivered” on Hubspot can still land in spam.

To verify placement, send your email to a seed list across Gmail, Outlook, and Yahoo and check where it lands. 

5. Check domain reputation and blacklist status

If your domain or sending IP is flagged, inbox placement will drop regardless of what you fix elsewhere. This is especially relevant for Marketing Hub users on shared IPs and for Sales Hub users with new or inactive domains.

One of the biggest sources of confusion is HubSpot’s Email Health tool.

It only applies to Marketing Hub emails and requires a minimum send volume to show meaningful data. It does not track:

• Sales Hub sequences
• 1:1 emails
• Any email sent through a connected inbox

This has been repeatedly clarified in HubSpot Community discussions, but it still trips people up.

If your sequences are landing in spam and you’re relying on Email Health, you’re looking at the wrong dashboard.

Once you’ve identified the path:

• Marketing Hub issue → focus on authentication, list quality, and shared IP reputation
• Sales Hub issue → focus on mailbox reputation, warmup, sending behavior, and tracking

How Do You Fix Marketing Hub Emails Going to Spam?

Marketing emails sent through HubSpot don’t behave like emails sent from your personal inbox. They go out through HubSpot’s shared sending infrastructure, which means inbox providers evaluate them using a mix of:

• Your domain reputation (how your audience engages)
• HubSpot’s IP reputation (shared with other senders)
• Your technical setup (authentication and compliance)

You don’t control the IP layer but you control everything else. The goal is to build strong domain trust signals that outweigh any shared-IP risk.

1. Fix Authentication (SPF, DKIM, DMARC)

If authentication is missing or misconfigured, inbox providers either filter your emails or reject them entirely.

You need all three protocols working and aligned:

• SPF (Sender Policy Framework): Tells inbox providers which servers are allowed to send emails for your domain.
  
  • Add: include:<portal-id>.spf01.hubspotemail.net
  • Make sure you have only one SPF record (multiple records break validation)
• DKIM (DomainKeys Identified Mail): Adds a cryptographic signature to each email so providers can verify it hasn’t been altered.
  
  • HubSpot gives you two CNAME records (hs1, hs2)
  • Both must resolve correctly for DKIM to pass consistently
• DMARC (Domain-based Message Authentication, Reporting & Conformance): Ties SPF and DKIM together and tells inbox providers what to do if authentication fails.
  
  • Start with p=none (monitoring mode)
  • Move to quarantine, then reject once stable

Authentication doesn’t guarantee inbox placement but without it, you don’t even qualify. Google and Microsoft now enforce these checks strictly.

Common failure points:

• SPF exceeding lookup limits or duplicated records
• DKIM broken by DNS misconfigurations (especially with Cloudflare proxy/flattening)
• DMARC not aligned with your “From” domain

2. Understand and Work Around Shared IP Risk

By default, Marketing Hub uses a shared IP pool. That means your emails are sent from the same IP addresses as other HubSpot customers.

Implications:

• Your deliverability is partially affected by other senders’ behavior
• A spike in spam complaints from another account can impact you
• You may see inconsistent placement, especially in Outlook

You can’t control who you share the IP with but you can protect your own reputation signals:

• Keep complaint rates extremely low
• Avoid sending to disengaged users
• Maintain consistent engagement patterns

3. Fix List Quality (This Is Where Most Problems Start)

If your emails are going to spam, list quality is often the root cause. Inbox providers track how recipients interact with your emails over time:

• Do they open and click?
• Do they ignore or delete?
• Do they mark you as spam?

Poor engagement sends a clear signal that this sender is not wanted.

What to do:

• Send primarily to contacts who engaged in the last 30–90 days
• Remove or suppress inactive users regularly
• Never upload purchased or scraped lists
• Verify email addresses before importing (to reduce bounces)

If you moved from another ESP (like Mailchimp), your old reputation does not transfer. You’re effectively starting from scratch on HubSpot’s IPs, which is why open rates often drop sharply after migration.

The fix is to rebuild engagement gradually, starting with your most active users.

4. Control Sending Volume and Patterns

Inbox providers don’t just look at what you send but also how you send it.

Risky patterns:

• Sudden spikes in volume
• Large campaigns to cold or mixed-quality lists
• Long gaps followed by heavy sends

These look like spam behavior even if your content is legitimate. Here are a few best practices:

• Start with smaller, high-engagement segments
• Increase volume gradually over time
• Maintain a consistent sending cadence

This helps stabilize your reputation on HubSpot’s infrastructure.

5. Test Inbox Placement Before Every Campaign

HubSpot shows whether an email was delivered, but not where it landed because an email can be:

• Delivered → but in spam
• Delivered → but in promotions
• Delivered → but never seen

To fix deliverability, you need to measure inbox placement, not just delivery rate.

One reliable way to do this is to send your email to a seed list across Gmail, Outlook, and Yahoo and check placement before your actual campaign goes out.

This is where MailReach’s email spam test adds a layer HubSpot doesn’t provide.

Instead of testing against a single inbox or relying on forwarded results, MailReach has you send your email directly to a distributed network of inboxes across major providers. It gives you a more accurate, unbiased view of placement across real environments.

• Inbox placement visibility across 30+ mailboxes: see exactly where your email lands (inbox, spam, promotions) across providers
• Unbiased spam score: based on real inbox placement, not simulated or forwarded tests
• Full technical checks in one run: SPF, DKIM, DMARC validation, blacklist status, links, HTML structure, and spam triggers
• Actionable feedback tied to your actual email: not generic advice, but issues specific to your content and setup

Instead of sending and hoping for the best, you test under real conditions, fix what’s flagged, and only then send at scale because once a campaign goes out, you can’t pull it back.

6. Decide If (and When) a Dedicated IP Makes Sense

HubSpot offers dedicated IPs for high-volume senders (typically 100K+ emails/month), along with an automatic warmup period but this is not a shortcut to better deliverability.

• On a shared IP, your reputation is blended with others
• On a dedicated IP, your reputation is entirely your own

If your engagement is strong and your list is clean, a dedicated IP gives you control.

If not, it concentrates all negative signals, low opens, complaints, bounces, onto a single IP, which can hurt you faster and more aggressively.

In most cases, it’s better to fix engagement and list quality first, then consider a dedicated IP later.

How Do You Fix Sales Hub Sequences and 1:1 Emails Going to Spam?

Sales emails sent through HubSpot behave very differently from Marketing Hub emails because they are not sent from HubSpot’s servers. Instead, they go out through your connected Gmail or Outlook inbox. HubSpot is only handling the automation, like scheduling, tracking, and sequencing.

For inbox providers, these emails look exactly like messages sent manually from your mailbox.

That’s why this problem is often confusing:

• The same email lands in the inbox when sent manually
• The same email lands in spam when sent via a sequence

Nothing about the content changed. What changed is how the email was sent and how your mailbox is being evaluated at scale.

To fix this, you need to focus on mailbox-level trust signals, not ESP-level fixes.

1. Understand What Inbox Providers Are Evaluating

For Sales Hub emails, there’s no shared infrastructure to lean on. Everything comes down to your mailbox.

Inbox providers evaluate:

• Mailbox reputation: How your domain and inbox have behaved over time
• Engagement signals: Replies, opens, spam complaints, deletions
• Sending behavior: Volume, frequency, and consistency

Unlike Marketing Hub, there’s no buffer here. If your signals are weak, your emails go to spam, no matter how good your setup looks.

2. Build Trust with Email Warmup

If your mailbox is new, inactive, or suddenly sending at scale, it won’t be trusted.

Inbox providers like Google and Microsoft expect a gradual, human-like sending pattern. When they see a spike in outbound emails without history, they flag it. Email warmup solves this by building that history before you scale.

It works by creating real, positive interactions with other inboxes:

• Emails are opened
• Replied to
• Marked as important
• Pulled out of spam folders

These signals tell inbox providers that your emails are wanted. Over time, this:

• Builds sender reputation
• Reduces spam placement
• Allows you to safely increase sending volume

Not all warmup tools work the same way. What matters is who is interacting with your emails and how realistic those interactions are.

MailReach is built around generating the exact signals that Google and Microsoft use to evaluate trust.

• Your emails are automatically sent to a network of 30,000+ real Google Workspace and Microsoft 365 inboxes because these are the same providers that filter your outbound emails, so the engagement carries real weight
• Those inboxes generate genuine engagement, opens, replies, marking emails as important, and pulling messages out of spam. These are the exact positive actions inbox providers look for when building sender reputation.
• Sending volume is increased gradually over time, so your mailbox builds history in a natural pattern. This avoids the sudden spikes that typically trigger spam filters on new or inactive accounts.

At the same time, MailReach gives you a provider-level view of your reputation, so you can see how Gmail and Outlook are treating your mailbox separately and catch issues before they affect your campaigns.

Instead of just simulating activity, this approach focuses on building measurable trust with the same systems that decide whether your emails land in the inbox or spam.

3. Fix the Tracking Pixel Issue

HubSpot adds an invisible tracking pixel to Sales emails to measure opens and clicks.

In many corporate environments, especially stricter Microsoft Outlook setups, this gets flagged as suspicious.

This creates a very specific pattern:

• Email without tracking = lands in inbox
• Same email with tracking = lands in spam

So:

• Turn off open and click tracking for sensitive sequences
• Use plain-text emails for high-value outreach
• Test both versions to confirm if tracking is the trigger

Tracking is useful for analytics, but it’s not worth sacrificing deliverability.

4. Control Sending Volume and Pace

HubSpot sets limits (500/day for Professional, 1,000/day for Enterprise), but these are technical caps, not safe limits.

Inbox providers care more about how you send than how much you send.

Risky patterns include:

• Sending hundreds of emails from a new or inactive inbox
• Sudden spikes in daily volume
• Bulk enrolling large lists into sequences

Safer approach:

• Start small (20–50 emails/day)
• Increase gradually as reputation improves
• Spread sends throughout the day
• Keep daily volume consistent

5. Write Emails That Generate Replies

For Sales Hub, replies matter more than opens.

Inbox providers track whether recipients:

• Respond to your emails
• Continue conversations
• Ignore or delete your messages

A high reply rate is one of the strongest positive signals you can send. Here are a few best practices to generate high reply rates: 

• Short, plain-text emails
• Natural, conversational tone
• Clear, simple ask (not multiple CTAs)
• Personalization that goes beyond placeholders

Templates that look automated tend to get ignored. Ignored emails weaken your reputation over time.

6. Test Your Emails Before You Scale

One of the biggest mistakes is enrolling contacts into sequences without testing where the emails actually land.

HubSpot will show “delivered” but that doesn’t tell you if the email reached the inbox.

To verify placement, send your email to test inboxes across Gmail, Outlook, and Yahoo and check:

• Inbox vs spam placement
• Differences across providers
• Impact of links, formatting, or tracking

Why Does HubSpot’s Tracking Pixel Trigger Spam Filters?

When you send emails through HubSpot Sales Hub, tracking is enabled by default. It works by inserting a 1×1 invisible image (tracking pixel) and rewriting your links so clicks can be measured.

On the surface, this is standard email marketing behavior. The problem is how modern spam filters interpret it, especially in B2B environments.

What the Tracking Pixel Actually Does

When your email is opened, the recipient’s email client loads a tiny, invisible image hosted on HubSpot’s servers. That request:

• Confirms the email was opened
• Logs device, time, and sometimes location
• Ties the open event back to your HubSpot activity feed

For click tracking, HubSpot also:

• Rewrites your links to pass through its tracking domain
• Redirects the user to the final destination after logging the click

These mechanisms are not inherently “bad,” but they change the technical footprint of your email and that’s what spam filters evaluate.

Why Spam Filters Flag It

Modern filters used by Microsoft (Outlook/Exchange), Google (Gmail), and enterprise security gateways analyze behavioral and structural signals of your emails. Tracking pixels and rewritten links can trigger flags for a few reasons:

1. Mismatch Between Sender and Tracking Domain

Your email might be sent from your domain (e.g., yourcompany.com), but the tracking pixel and links often point to a different domain controlled by HubSpot.

To a spam filter, this looks like:

• Sender: yourcompany.com
• Tracking activity: hubspotemail.net (or similar)

That mismatch can resemble phishing or spoofing patterns, especially in stricter corporate environments.

2. Hidden Elements Inside the Email

The tracking pixel is intentionally invisible. It’s a 1×1 image with no visible content.

Spam filters treat hidden elements cautiously because:

• They’re commonly used in tracking and surveillance
• They’ve historically been used in malicious or deceptive emails

A single pixel won’t always trigger spam, but combined with other signals (low reputation, new sender, high volume), it can push the email over the threshold.

3. Link Rewriting and Redirect Chains

HubSpot rewrites links for click tracking. Instead of linking directly to your destination, the email routes through a tracking URL first.

This introduces:

• Redirect chains
• Non-matching domains
• Additional HTTP requests before reaching the final page

Spam filters often score emails negatively when:

• Links don’t match the visible domain
• Redirect behavior looks suspicious
• Multiple tracking parameters are present

4. Corporate Security Filters Are Stricter

This issue shows up most often with recipients using enterprise email systems, especially Microsoft Outlook in corporate environments.

These systems are configured to:

• Block external images by default
• Scan tracking pixels as potential data leaks
• Flag emails with tracking + low engagement as risky

That’s why you’ll often see:

• Gmail → inbox
• Outlook (corporate) → spam

Same email, different filtering rules.

If you suspect tracking is affecting your deliverability, test and adjust:

• Disable open and click tracking for sensitive sequences
• Send important emails as plain text (no HTML, no tracking)
• Test the same email with and without tracking using a seed list
• Avoid heavy link usage in early outreach emails

For high-stakes outreach, especially to enterprise prospects, deliverability matters more than tracking visibility.

Tracking is still useful when:

• You’re emailing warm or engaged contacts
• You need performance data for campaigns
• Deliverability is already stable

But for cold or semi-cold outreach, especially in Sales Hub sequences, tracking can become a liability.

Warm up your connected mailbox with MailReach

Sales Hub emails are judged entirely by the reputation of your connected inbox. If that mailbox is new, inactive, or suddenly sending at scale, inbox providers don’t trust it and your emails get filtered before content even matters.

MailReach is built specifically for this use case. Its warmup network is made up of real Google Workspace and Microsoft 365 inboxes, the exact same providers that process and evaluate your Sales Hub emails. 

Here’s how the warmup actually works in practice:

• Your mailbox starts sending controlled volumes of emails into MailReach’s network of 30k+ real business inboxes
• Those emails receive positive engagement signals, like opens, replies, marked as important, and pulled out of spam folders
• These interactions happen as natural conversations, which makes the signals credible to Gmail and Outlook
• Volume ramps up gradually over time, avoiding the sudden spikes that typically trigger spam filters

These are the exact signals inbox providers use to evaluate sender quality. As they accumulate, your mailbox reputation strengthens, making it safer to run sequences without getting filtered.

However, warmup alone isn’t enough if your templates trigger filters.

Before enrolling contacts into a sequence, run your emails through MailReach’s spam test. This shows where your message lands across Gmail, Outlook, and other providers, and flags issues in your content, links, or authentication that could hurt placement. 

Finally, track your progress continuously. MailReach provides a reputation score by provider, so you can see how Gmail vs Outlook specifically views your mailbox. That visibility helps you adjust sending volume, pause sequences when needed, and avoid reputation drops before they turn into deliverability issues.

What Content Mistakes Trigger Spam on Both Paths?

Even with strong authentication and a healthy sender reputation, a single email can land in spam because of how it’s written or structured. That’s because inbox providers score each message individually, not just the sender behind it.

There are two separate layers at play:

• Sender reputation → built over time (domain/IP history)
• Content scoring → evaluated per email

You need both to be clean. A good reputation won’t fully save bad content—and bad content can quietly kill otherwise healthy campaigns.

These are the patterns that consistently push emails toward spam across Google (Gmail), Microsoft (Outlook), and Yahoo:

1. Spam-Style Language and Formatting

Certain patterns are strongly associated with promotional or low-quality email:

• Overly aggressive subject lines (“Act now”, “Limited time”, “Last chance”)
• Excessive capitalization or punctuation (“FREE!!!”, “URGENT!!!”)
• Heavy use of sales or money-related claims
• Long, cluttered subject lines trying to do too much

Individually, these won’t always trigger spam but combined, they increase your risk significantly.

2. Overly Complex HTML and Design

Emails that are heavily designed often carry more risk than simple ones.

Common issues:

• Too many nested tables or complex layouts
• Excessive inline styling or scripts
• Poor rendering across devices

Spam filters prefer clean, lightweight HTML. Over-engineered emails look more like mass marketing blasts than personal communication.

3. Poor Text-to-Image Balance

Emails that rely heavily on images, especially with very little text, are harder to evaluate and easier to flag.

Examples:

• Image banners with minimal supporting copy
• Entire emails built as a single image
• Broken or blocked images (common in corporate inboxes)

Inbox providers rely on text to understand intent. If there’s not enough of it, the email becomes harder to trust.

4. Suspicious or Broken Links

Links are one of the most heavily analyzed parts of an email.

Risk factors include:

• Mismatch between displayed text and actual URL
• Redirect chains (especially with tracking)
• Links to low-reputation or flagged domains
• Shortened URLs or overly parameterized links

Even one problematic link can push an otherwise clean email into spam.

5. Missing or Hidden Unsubscribe Options

For bulk emails (especially in Marketing Hub), this is critical.

• No unsubscribe link → immediate trust issue
• Hard-to-find or disguised unsubscribe → negative signal
• Non-functional unsubscribe → complaint risk

Inbox providers expect a clear way for users to opt out. Hiding it increases spam complaints.

Across both HubSpot paths, content performs best when it is:

• Simple and easy to read
• Light on formatting and design
• Clear in intent and audience relevance
• Free of unnecessary links and tracking clutter

Inbox providers are optimized to reward emails that look and behave like real human communication.

The closer your email gets to that, the more consistently it lands in the inbox.

Fix the Right HubSpot, Fix the Spam Problem

Deliverability problems usually build up quietly with small gaps in setup, inconsistent engagement, changes in provider rules and only show up when performance drops.

What separates teams that recover quickly from those that stay stuck isn’t access to better tools but how they treat deliverability. The teams that consistently land in the inbox treat it as an ongoing system they monitor, test, and adjust.

That means: 

1. Checking where emails actually land, not just whether they were delivered. 
2. Validating changes before sending at scale. 
3. Knowing when a drop is a content issue, a reputation issue, or a platform-level constraint and acting on the right one.

Start testing where your HubSpot emails actually land. Try MailReach’s email spam test.