10 Reasons Why Your Emails Go To Spam & Improve Email Deliverability

Stop emails going to spam
Published 27 December 2021

Last updated on 5 July 2022

If you send frequent newsletters or use some other type of email marketing, you certainly don’t want to have your emails going to the spam folder of your subscribers. Knowing how to avoid deliverability issues and have your emails delivered to your subscribers’ inbox is an important point to learn about.

This guide was created to help you avoid spam traps and get your emails directly to the recipient’s inbox.

Online tool to help find out if your email is spammy

There are a number of online tools to help you create the best possible emails and to check how spam-proof your email is. One of them is Mail Tester. This tool, together with the guide below, will enable you to improve your sending practices and get your emails to your recipients’ inbox folders.

You need to ask yourself

Ask yourself the question after looking at your email – “Does my email look spammy?”. If you think it does, then it probably is.

Important Terms

There are a couple of terms used in this guide that are important enough to be explained separately. They will help you understand this topic in more depth.


Though you can probably make out what the word ‘deliverability’ means, it will not hurt to define it again. In dictionaries, this word is explained as the quality or possibility to be delivered. If we take it out of the books and into the real world, we may say that ’email deliverability’ refers to the extent to which your emails reach the primary inbox of your recipients.

When we talk about Gmail, it is worth noting that your email may go to the Promotions tab. This usually happens when you use a third party or email marketing tool. It can also occur with emails that have commercial content. But that is okay, as long as the emails aren’t in the spam folder.

In the continuation, you will be presented with 10 ways to improve your email deliverability. They aren’t definite ways to prevent your emails from going to spam without error, but they will help you improve this immensely.

Sender Reputation

Man standing confused

This is a score that you get from your ISP (internet service provider). Based on this score, your emails will be delivered to your recipients’ inbox or spam folders, or, in the case of a very bad score, not delivered at all.

Some of the factors that are taken into account when calculating your sender reputation are:

  • The number of emails you send.
  • User behavior: opening, replying, or sending your emails forward.
  • How many people click on the links within your emails.
  • How many spam complaints are made regarding your messages.
  • How many of the emails bounce due to invalid addresses.
  • How many users unsubscribe.

These are some of the things that are taken into account. And hence you have more reasons to improve the deliverability of your emails and keep your score high.

Methods to avoid emails going to spam

1. List hygiene & cleaning

Maintaining list hygiene means that you should take time once in a while to clear your list from the email subscribers that don’t seem interested in reading your emails anymore but who haven’t hit the Unsubscribe link.

How often you will get down to removing unengaged users is entirely up to you – some people do it once in six months, others in nine, and yet others in twelve months.

Why it’s bad to email everyone on your list

You may think that it is great to have as many subscribers as possible, but let’s look at this from another angle. If you have a huge number of inboxes to reach, your email deliverability rate will decline.

That presents the possibility that some people who are interested in your content may not get your emails altogether. But if you have a somewhat shorter list of people who are actually engaging by opening and reading your emails, or even clicking links and buying the products you advertise, your sender reputation will be better, and you will also be able to reach more people who can really make the difference for your cause.

Try to re-engage non-openers

It is okay if you are reluctant to delete someone off your subscriber list. And the good news is that there is something you can do to make sure that it is okay to remove them – a re-engagement email campaign.

Basically, this would include a set of two or three emails in which you would say that you noticed a recipient hasn’t opened your email and ask them whether they wish to keep receiving email messages from you. In this case, you need to add a link or a button in a follow-up email for them to click and get reinstated as your regular subscribers.

Also, it is a good idea to use an email service for the validation of addresses. A tool like this is used for weeding out any emails that are invalid or to which an email message cannot be delivered. Sending emails to these addresses is also bad for your sender reputation.

Clean your email list of subscribers that don’t engage

Another tip is to delete the email from people that do not engage or open your emails. A recommended amount is:

  • Not opened email in 180 or 365 days
  • Not opened an email in 180 or 365 days
  • Not ordered a product in 7 days

Of course, you can customise these to suit your store best. But these are the best solutions to finding emails that aren’t engaging.

Not opened email scaled
Klaviyo email app

Read more on cleaning your email list.

2. Double Opt-In (Confirmed Opt-In)

A double opt-in is one of the email authentication methods, more precisely, a way to confirm that a person really wants to subscribe to your list and hasn’t clicked the button accidentally or any spam bots have entered spammy emails. (Look above to see why quality is more desirable than quantity).

This requires the process after someone has clicked on the Subscribe button and then they need to go to their inbox, open the email and click on a link to confirm the subscription.

The double opt-in process may have one additional thing your Gmail subscribers need to do, should you choose to ask them. That is asking them to whitelist your address. This is done by dragging any of your emails from the Promotions folder to the Primary inbox.

3. Spam Trigger Words

There are certain spam trigger words that lead mail servers to send your emails to the spam folder. These words are the ones usually used in commercial and spam emails. When I talk about these spam trigger words, I am thinking about the subject line.

Subject lines that are problematic usually make big promises and/or ask for people’s sensitive info. Even though you can find extensive lists of words to avoid, remember that it is okay to use some of them when you need them. If you follow the other guidelines to avoid spam filters, you will be fine.

Some of the words that should be avoided are much as possible are:

  • 100%
  • Free gift
  • Incredible deal
  • Click here
  • Order now
  • Earn extra cash
  • Risk-free
  • Join millions
  • Guaranteed
  • Bargain
  • Amazing
  • Free

Also, the things to avoid are emojis, misspelling, bad grammar, all caps, and repeated punctuation marks (such as !!!!! or ????).

4. Verify your sending domain

Making a verification of your domain is basically like getting a license to send your marketing emails. This adds to your sender reputation and in this way, your email service provider knows that you are legitimate and that your emails don’t have to be marked as spam. There is no need to repeat this process when you have done it; once is all it takes.

Another reason for doing this is your own security, as registering your domain will not allow hackers to use your domain and send fraudulent emails to your subscribers.

The way to do it is through the DNS (Domain Name System, this is like an internet address book) settings. There are two main items to enable. One is SPF (Sender Policy Framework) that lists all the IP addresses from which you will send your emails. The other one is DKIM (Domain Keys Identified Mail) which consists of a private key (which only you know) to encrypt your signature and a public key (which becomes familiar to the recipients’ servers) to decrypt the signature.

5. Correct IP allocation

Hopefully, the number of subscribers on your list will grow, and with that, you may have the need to use more than one IP address for sending your emails. The reason for this split is that any one of the inbox providers has a limited number of messages that one connection can handle.

This depends on your servers just as much as on the servers of your recipients. So, if you have a strong server, such as Google’s, you will be able to send a great many messages. If your subscribers are mostly Gmail users, this will go smoothly.

But if most people on your list use smaller and thus weaker, servers, the need for an additional IP address may come more quickly than you have originally planned.

One thing to be careful about is not to spread your emails to an unnecessary number of different IPs. Your internet service provider may see this as suspicious because this kind of action is usually done by people who have dishonest intentions.

6. CAN-SPAM Act of 2003

The full name of this act is Controlling the Assault of Non-Solicited Pornography And Marketing (CAN-SPAM) Act of 2003. It is the first of several laws that shape the standards for email marketing.

Following is a shortened list of the rules to obey:

  • A visible and easily-found Unsubscribe button.
  • 10 business days at most to put a user’s opt-out in effect.
  • Subject lines with an accurate description of the email content.
  • The real physical address of the sender.
  • The content must have at least one sentence.

7. Don’t buy or get email leads

Boosting your email campaigns by obtaining leads is not a good practice. Though you may have more addresses to reach, remember that you don’t have the consent of your leads to send them emails. The engagement will probably be low and your score will go down. Many of them may choose to unsubscribe or even make spam complaints. All this will bring you more harm than gain.

Also, be aware that ISPs sometimes put spam traps in these lists. If you send your mail to one of them, you may get on the black list, and it is very very hard to get off this list.

When you send a private email to a colleague or a school friend, it is of no significance whether you will add none, one, five, or ten links. However, if you are sending a commercial email, the inbox provider will view your message as promotional if it contains many links.

There isn’t a definite number that is too small, too big, or just enough. The only thing you can do is bear in mind that you should keep the number of links within your email to a minimum.

Avoid linking to spammy domains

There are a lot of domain extensions (TLDs) that are classed as spammy to service providers. You can read more about TLDs here.

9. Regular schedule

Being consistent in how often you send out our emails is a sign for your email provider that you are legitimate and don’t send spam.

This is a tricky decision to be made as it involves having regular content for a long period of time; nevertheless, it is the way to keep the spam checkers from directing your mail to where you don’t want it to go.

Another good side is that your subscribers will be aware of when your messages arrive and will be expecting them. The user engagement is thus improved and unsubscribing reduced.

10. Send emails that make people happy

The last thing on our list of ways to improve your email deliverability is maybe the most important one. The recipients of your emails should be satisfied with what they get. The greater the satisfaction, the greater the interaction. With that, you will also show your email service providers that you send legitimate emails which are safe to reach the inboxes of the recipients.

How can you keep your subscribers happy with what comes to their inbox? There are two basic things to do:

  1. Keep the content useful and to the point. People want to get high-quality stuff and will interact with it.
  2. If you can, let them choose how often they want to get emails from you. A little bit of control can make a huge leap in customer satisfaction.


Email deliverability is an important thing to deal with when you are an email sender and have a long list of email clients. Your messages may land in a spam or junk folder, so it is a good idea to do everything you can to avoid spam filters before hitting Send. The text above shows you some of the good sending practices that can help you to prevent your emails from getting marked as spam. Learn more about the reasons why your emails land in spam and how to improve your email deliverability.


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