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Why Are My Emails Going to Spam? The 14 Reasons and 4 Most Effective Solutions. 

Damien Brenelière
Co-Founder @ MailReach & Email Deliverability Expert

Why are my emails going to spam? We have been replying to this question for years now. There are many factors that can cause spam but here are the ones responsible of 90% of it. And, of course, we give you no bullshit solutions to fix that ASAP.

Why are my emails going to spam | an email going to spam

You’ll find here the top causes of land in the spam folder according to our data.

Since two years, MailReach has gathered and analyzed the data of dozens of thousands of deliverability tests.

Combined with our experience, we can now list the most frequent causes of landing in the spam folder.

These causes are related to authentication, your content, your way of sending emails, your sending reputation.

At the end of the article, we list the best solutions to help you land back in inbox instead of the junk folder.

1. You’re not properly authenticated (SPF, DKIM).

Not having the SPF and DKIM records properly set up in your DNS zone can make you send your emails directly to spam. We see that happen every day.

We know it’s boring…

But you need to set those up properly to avoid authentication problems that can lead to landing in the trash folder.

DMARC is not a game changer for now but we recommend you to set it up as well.

It takes 5 minutes. Just do it.

You’ll see that in the “Solutions” part below. MailReach’s free deliverability test will help you know if you’re properly authenticated.  

2. You have a low engagement rate on your emails which causes spam.

Today, and much more than before, the major inbox providers (Google and Microsoft) use engagement as a factor to score your sender reputation and filter your emails.

That’s simple, when sending emails, if you don’t receive enough positive interactions (openings, clicks, replies, messages marked as important, removed from spam), then you will land more and more in spam.

Why? Because engagement is an effective way for the big providers to score your activity.

An interesting sender receives many positive interactions.

An uninteresting sender does not receive much positive interactions. Result? Let’s put his emails into the trash folder.

Whether you send marketing emails, transactional or cold emails, you need a high engagement rate to maintain a high reputation.

ReturnPath, the global leading company in email deliverability (acquired by Validity) says, in their Gmail Deliverability Best Practices page, in the Gmail’s top deliverability factors section, the following :

“When encountering deliverability issues at Gmail, temporarily sending only to your most engaged subscribers […] can help improve your sending reputation and lead to an increase in inbox placement. Gmail uses engagement as a factor for filtering your email.”

Sendgrid, one of the major email sending services says, in one of their posts, the following :

“The higher your email engagement, the more likely you are to avoid spam filters and land in the inbox.”

Campaign Monitor, in their guide to avoid spam filters, says :

“Now, whenever you send a new campaign, inbox providers like Gmail and Outlook actually look at their user engagement and previous interactions with your past campaigns. They then use this information to determine whether your latest campaign makes it to the inbox or not.”

That’s therefore a proven fact (backed by our data) that having a high level of engagement helps a lot to improve email deliverability.

We’ll cover how to fix that in the solutions below.

3. You include attachments, a very spammy practice.

Including attachments in your emails can be easily associated to phishing and hacking. That's simple, if your emails contain one or several attachments, then your risk of ending in spam is much higher.

For a couple 1-to-1 emails to people you know it can be fine. But never in bulk and especially to people you've never contacted.

If you want to share a document, you can use a tool like DocSend that allows you to include a link to your doc.

4. You include shortened URLs, which is a spam practice.

Using URLs shorteners such as Bitly links in emails makes you land in the junk folder. That’s just awfully bad for deliverability and that's a major reason email spam filters put you in spam.

Why? Because it’s used by spammers to hide links and Google and Microsoft hate that.

The result is simple, it makes you send your email directly to spam.

Avoid using URL shorteners at all costs, that’s a true deliverability killer.

5. Your emails contain links that are not liked by spam filters.

First, you may link to a website that looks spammy in some way to email spam filters.

For example, if the URL is broken, if the website is not https / protected by a SSL certificate, or if it’s infected by a malware or for some other reason.

The site may be totally legitimate, but could very close to another domain that is spammy.

Secondly, if the destination URL does not match the display URL, it may cause spam.

Let’s say the display URL is xyz.com but the actual link is anotherwebsite.com, you may run into problems as this is a common tactic used by spammers to trick people into clicking on links.

That’s the same thing for URL shorteners (like mentioned above).

6. You’re not using a custom tracking domain. A major cause of landing in spam.

When you use an email service provider for your campaigns, by default, a tracking pixel is automatically inserted in each of your messages.

This tracking pixel is always associated to an URL / a domain and that what allows you to know and monitor how many people open your email, your opening rate, click rate, etc.

By default, the tracking domain added in your email is the same as the other users of your automation tool. And that’s the problem.

That means your emails contain the same tracking domain as other customers of your sending provider. In other words, you’re sharing a domain / URL with a lot of other people and businesses using this email service.

The problem is this : if you don’t set up your own custom tracking domain, your emails will be associated to all the customers of your email automation tool who did not set up their own custom tracking domain.

If you use an email automation tool, set up a custom tracking domain. That’s mandatory to have a good deliverability. If your current tool doesn’t allow it, change it.

7. You don’t include an easy-to-spot unsubscribe link.

This is crucial.

If there isn’t a clear unsubscribe link in your email then you get much more spam complaints, that’s mathematical.

And no, saying “to unsubscribe, reply unsubscribe to this email” does not help. Most people don’t care about replying to your message, they just mark your email as spam and ciao.

No clear unsubscribe link = more people mark your email as spam = damaged reputation = you miss customers = you lose money.

There’s no scenario in which not including an unsubscribe link is better for your results.

“But it looks less human if you have one”. NO, you can send 1-1 emails and have an unsubscribe link. That’s just respect and UX for the recipient.

We’ve compared campaign results between having an unsubscribe link VS not having one and there’s no major difference in terms of leads.

In the long run it even generates more sales as you’ll land more often in inbox.

8. You receive too many spam complaints.

In 2023, having your messages marked as spam is very damaging for your sender reputation. It sends a strong signal to the inbox providers that at least some of your emails are considered as spam.

Here are the most common reasons people can mark as spam :

  • Your message is irrelevant for them or contains an error they didn’t like (‘Hi Last Name’ for example)
  • Your message is too pushy or salesy
  • It’s difficult to unsubscribe
  • They don’t like your offer, brand or name
  • Your message pisses them off in some way
  • They're over sollicited

You need to please your email list, make sure to remove the irrelevant people and send them solutions to their problems.

9. Your email includes spam triggering words.  

First, there are very sensitive topics where spam words are omnipresent.

Discounts, earning money, saving money, money in general (discounts, salary, etc), health, medication, weight loss, diets, games, sex, and many more. 

If you talk about any of these topics, your risk of having your emails go to junk because of spam words is much higher. 

BUT, there are many unsuspected words that you wouldn't expect. 

Spam words are not always the ones you think. Now, the inbox providers / spam filters use machine learning to flag spam words.

Now, any word can be a spam word. 

For example, let’s say that tomorrow, nasty spammers start spamming the world with messages containing the word “Yoga” and a lot of people report their emails as spam. “Yoga” can then become a spam word because spam filters / algorithms have associated this word to spam. Understand?

10. You’re using aggressive punctuation and/or wording.  

Eliminate any aggressive punctuation in the subject line and in the body. That's a very common reason email spam filters use to put you in the junk folder.

Typically, avoid the “!!!“ like “That’s the best offer of your life!!!!”. It will make your emails go to the junk folder.

Also, make sure to avoid WRITING LIKE THIS, LOL.

11. You send too many emails, like a spammer does.

We see that every day at MailReach. A lot of people and companies land in the spam folder because they just send a lot of emails, too many emails per day.

One of the golden rules of deliverability is to have the most human behavior.

You need to act as an interesting person who sends emails and gets a lot of engagement (openings, replies, marking as important, saving from the spam folder).

For a cold emailing activity :

150 cold emails daily per sending address and domain should be the maximum to maintain a good cold email deliverability. The fewer the better. If you can limit to 100, do it.

Why per email address AND domain?

Because if you have several email addresses per domain, if one gets flagged as spam, it will spread on all the other ones, it's just a matter time as the reputation is shared on the domain level. 

By having only one email address per domain, you minimize the volume of emails sent on the domain level (which is better for your engagement rate / reputation / deliverability), and you minimize the risk of spam spreading between your addresses

And If you exceed 150/200 daily per email address, the risk of having deliverability issues is much higher.

For an opt-in / transactional / marketing email activity :

For an opt-in / transactional / marketing emails use case, you can have a higher daily volume per domain.

But you still need to have a high engagement rate.

12. You send your emails from a custom SMTP or any exotic email service provider.

The major inbox providers, Google and Microsoft can easily find out where your email comes from and flag it as spam based on that.

They can know what you’re using to send emails. They can identify your email service provider.

And the way you send emails is very, very important.

Why?

Because some inbox providers / SMTP providers are more spammy than others.

From our data, we can tell that using Google Workspace inboxes (Professional Gmail) is the best in terms of deliverability.

Professional Outlook (Office 365 / Exchange) comes in second position.

On the other hand, sending from a Custom SMTP is the worst to land in inbox. Because it’s too exotic and this is the #1 setup used by spammers.

If you want to land in inbox, choose the most human way to send an email.

And guess what, the best way to send cold emails is to use Gmail (Professional for B2B) or Exchange / Office 365.

If you don't send cold emails but opt-in / promotional / transactional emails, choose well known, reputable email service providers such as Sendinblue to avoid having the spam filters put you in the junk folder.

13. Your sender reputation is too low.

This one is often linked to the “You have a low engagement rate on your emails.”

If your domain’s reputation and/or your IP reputation is damaged, you’ll suffer from landing in the spam folder

Remember the following :

Good deliverability = good email reputation (IP, domain) + not spammy email content + not spammy sending setup.

You need to combine the 3 to land in inbox.

Most of the time, an email reputation can be damaged because of the previous email activity of your domain and/or your IP.

If you have sent many email campaigns in the past and had very low engagement rates on these campaigns, your email reputation is very likely to be damaged which results in having your emails landing in spam.

The solution consists in generating more engagement on your domain and associated IPs.

We’ll cover that in the solutions below.

14. Your send too many follow ups (cold emailing use case).

For a cold email activity, sending follow ups is usual and considered as a best practice to get more sales.

We agree that it may be a best practice to generate sales BUT too many follow-ups can burn your email reputation and, as a result, make you land in the junk folder.

Why? Because follow ups are sent to people who didn't reply to your previous email. And a lot of people didn't reply because they're simply not interested. That means that, each time a follow up is sent, the uninterested people

The most effective solutions to stop having your emails going to spam.

First, run a spam test using MailReach. It’s free.

email deliverability tools | Mailreach Email Spam Test
Why are my emails going to spam ? Use MailReach’s Email Spam Test

After analyzing dozens of thousands of emails, we decided to develop a powerful email spam test to help measure your inbox placement and identify the potential problems in your emails.

This test is free to use and doesn’t require any account for up to 3 tests per 24 hours, enjoy!

You simply have to copy / paste a code inside your email and then send it to a list of email addresses.

Make sure to send an email under the same sending conditions as when you found out you landed in spam. Otherwise, the test will be biased.

MailReach will check your email and tell you where it landed on the major inbox providers with a score out of 10 with several checks and recommendations to improve your score.

It’s very important to measure your deliverability before trying to fix anything. You can’t improve what you don’t measure!

Follow the recommendations of the deliverability report and run another spam test.

email deliverability tools | Mailreach Email Spam Test
Why are my emails going to spam ? Follow MailReach recommendations.

You have done your first spam test and got your score. Now, you know how you’re doing and where your email land on the major inbox providers.

Make sure to check the tabs “Content” and “Setup” to see if MailReach detected potential issues or things to consider.

If there are things to improve, make the changes to your email and/or sending setup and then run a new test to see if you manage to get a better score.

If don’t manage to reach 10/10 and MailReach doesn’t give you anything to improve, it can be a strong indicator that you have a reputation issue.

See below for the next steps.

If you’re still in spam after making the recommended changes, use MailReach’s email warmer to raise your reputation.

email deliverability tools | MailReach email warm up service
Why are my emails going to spam ? Use MailReach’s email warm up service

If you’ve done all the improvements suggested by MailReach using the Spam Checker and you still land in spam on the inbox provider you target, then it may be a sign that your email reputation is damaged and you have to restore it.

Raising your reputation can be done by generating engagement on your email activity to show the email providers that you send interesting and relevant emails and deserve to land in inbox.

You have two ways to generate more engagement.

The 100% organic way

1. Send emails to your most engaged recipients by segmenting your email list.

2. Get better at writing emails to better engage your recipients and receive more positive interactions to your emails.

The smart, automated way

Use MailReach, the smartest email warming service to generate meaningful engagement to your emails and land more in inbox.

The mission of an email warmer like MailReach is to generate engagement with your inbox and domain to raise your email reputation and in turn, your deliverability.

You simply have to connect your inbox and MailReach will start conversations with other inboxes in the background.

Most of your warming emails will be opened, replied, marked as important and removed from spam. You then get plenty of positive interactions.

It literally teaches the email providers to put your emails in the inbox of your recipients.

To restore a damaged reputation with MailReach, we have a dedicated guide to get the best results as soon as possible: How to restore a damaged reputation and deliverability using MailReach.

Read our best resources to help you get the best deliverability of your emails.

With our strong experience and data on email deliverability, we have written very helpful and practical guides to help you maximize the deliverability of your emails. You'll find precious guidelines that nearly nobody talks about and that are crucial to get the best results from your campaigns.

The Ultimate, No Bullshit, Email Deliverability Guide : How to prevent emails from going to spam

For a cold emailing use case : The Best Cold Email Sending Strategy

Reading these two guides and applying our recommendation will drastically improve your deliverability.

Why are my emails going to spam : Final thoughts

It is becoming increasingly common to land in spam with the evolution of spam filters and algorithms. Keep in mind that sending emails is easy, making sure they reach the inbox is much more complex. You need to be very careful and use the right tools to help.

You have to use a reputable email service provider, avoid using spammy elements in your emails, test your deliverability with our spam test, and get enough engagement to maintain a good reputation.  

Remember that an imperfect deliverability means losing customers and money.

Using can be a real game changer to make sure to get the best results from your emails.  

MailReach is compatible with any inbox / SMTP

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