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Why Emails Go to Spam and How to Prevent It

Thoughts by Gracija Atanasovska • Writer Bento

Not a single marketer, even the most successful out there, hasn’t experienced email deliverability issues. In fact, it’s not unusual for your email to end up anywhere but the desired inbox.

There are a lot of factors that contribute to email deliverability, which sometimes makes it a tricky business. Even if you think you’ve got (almost) everything right - proper authentication, excellent email copy, and so on, your email may still end up in the spam folder.

But don’t worry. I’m here to tell you about the possible reasons why this might happen and what you can do to prevent it.

So stick around and let’s begin!

*TLDR: Email deliverability is more complex than you think. Your emails might end up as spam because you’ve purchased email lists online or provided inaccurate sender information, or there are too many spam triggers in the email, weak subject lines, or grammar errors in your email copy. You can ensure this doesn’t happen by building your own email lists, using double-opt, cleaning your email lists regularly, ensuring your emails have proper authentication protocols, and ensuring your email copy is well-written and relevant for your clients. *

Why Are My Emails Going to Spam?

Let’s go over why your emails might end up in the wrong place.

1. You’ve Obtained Email Addresses Without Permission

Rule number one regarding email marketing is you never get an email address without asking for permission first.

This means that you should never buy email addresses online. It’s unethical, and they’re also loaded with spam traps, which is super bad for business.

The email addresses you add to your list should only be there if the person behind them consented, usually through an opt-in registration.

2. Inaccurate Sender Information

All of your sender’s information, like the “From” and “To” elements, as well as “Reply-To” and the routing information (info about the destination address), have to be correct and properly identify the business/company and the people behind them.

That means that if you don’t clearly say who you are and if you include inaccurate, misleading information, your email is likely to end up in the spam folder.

3. You’re Using Spam Trigger Terms In Your Emails

Email spam filters are very diligent about the content of your email and the subject line and use them to decide whether the message ends up in the spam folder or the subscriber’s inbox.

Subject lines like: “Congratulations, you’ve won __!”, or “Win a free __”, “Double your earnings!” can definitely become a cause of concern for these spam filters.

Trigger words like “Earn extra money/cash/income”, “Congratulations __”, “No fees”, “Bonus”, “This is not a scam/spam”, as well as too many punctuation signs (especially exclamation marks) and emojis, can all be considered spam red flags by filters.

4. You Have Weak Subject Lines

Email subject lines are super important for your email open rates. It’s the first thing your subscriber/client sees in their inbox that makes them decide whether they will open the email or not.

In fact, do you know that 69% of recipients report that emails are spam based on their subject lines?

That’s why the trigger words I mentioned earlier should be avoided.

If your emails keep ending up in the spam folder, you may be doing this with your subject lines:

  • They sound like you’re giving false promises;

  • You’re using too many capital letters;

  • You sound too pushy;

  • Your subject lines don’t match the email content;

  • Your subject lines aren’t precise.

5. The Spelling and Grammar of Your Email Aren’t Exemplary

Errors in spelling and grammar are one of the first tell-tale signs of a spam or phishing email. That’s why you have to pay extra attention to them as well. Not to mention that spelling and grammar errors look very unprofessional in your subscribers’ eyes.

Now, I know that sometimes stubborn grammar errors can escape even the most diligent human checks, which is why it’s a good idea to put your text through a spell-checking tool, like Grammarly, for example.

6. Your Sending IP Has a Bad Reputation

The sending IP address is very important when it comes to deliverability. Much like real-life reputation, ESP (email service providers) keep track of your IP address history. The bigger the history of low spam complaints and low bounce rates, the more your sending IP becomes trustworthy for the ESPs. And vice versa - the higher the number of spam complaints and bounce rates, the less credible your sending IP is.

One of the reasons why your sending IP might have a bad reputation is if you’re using shared hosting (a shared email server). Its other users, who also use the same IP address as you, might be to blame because of their sending activity. I’m not trying to say that using a shared server and a shared IP is necessarily a bad thing - just that if you’re dealing with this issue, it can sometimes be due to bad co-sharers.

Another reason might be your new email IP address that hasn’t been properly warmed. When an email IP address is new, you have to start by sending a low amount of emails and then gradually increase the volume. If you send lots of emails from the very beginning, the ESPs might think you’re a spammer, and you risk being blacklisted or receiving spam complaints, all of which lower your IP reputation.

7. The Email Recipient Marked Your Email as Spam

When a recipient marks an email as spam, it can be due to several factors.

For example, your content might not be relevant to them because you haven’t done the proper list segmentation homework, or maybe the user is just not interested anymore. Another reason might be spam-like content or words within your email, clickbait subject lines like “Free…” or “You’ve just won…” or lots of exclamation marks and emojis. Maybe your email isn’t responsive to that particular recipient, so you may want to work on that. Or it might just be that the recipient's inbox is full, in which case, if you notice a pattern with a recipient doing this, it’s time to remove them from your list.

8. You’re Using Link Shorteners

While link shorteners (also called URL shorteners) might seem like a neat idea, oftentimes they can do more harm than good.

The problem is that shortened URLs are known to be used by cybercriminals in phishing scams. What they do is they use a shortened link that sounds more familiar and legitimate, and yet its aim is to collect information that might compromise you somehow (stealing your credit card number, for example).

That’s why some providers tend to blacklist URLs that have been shortened and that have generic, common-sounding domains.

9. Your Emails Don’t Have a Plain-Text Version

Plain-text emails are emails that don’t contain anything else besides text, like fancy visuals or hyperlinks. Including a plain-text version of your emails is important because spam filters, which prefer this stripped-down email message, use it to confirm that the email is indeed legitimate and not spam.

Plain-text is also good when your initial email design is having responsiveness issues. The simple version will allow it to load to every device and internet connection. What’s more, if your recipient is using an ESP that disables the loading of images, the plain text email will save your email from being discarded or unreadable.

Email providers usually have tools that help you edit and preview this format for your emails. It’s certainly a good idea to go over it before you click send to that email campaign that’s been long in the making.

How Can I Prevent My Emails From Ending Up as Spam

Next, I’ll tell you about some of the best practices you can follow to make sure your emails won’t end up in the spam folder.

1. Build Email Lists on Your Own

As I mentioned above, purchasing email lists online is one of the worst things you can do. Building and expanding email lists on your own is the way to go.

When you control your own lists, you know that people consented to be there and that you’re not including any unwanted spam traps. Also, with additional help from segmentation and curated lists, you can always send relevant information to your subscribers and clients, which also helps engagement big time.

2. Use the Double Opt-In Option for Email Signup

This one dovetails on the previous tip. The double opt-in option is important when you want to ensure that your subscribers want to be on your email list.

It usually means that once they put basic data in the signup box of your website, they’ll receive a welcome email or confirmation email containing a link which they will have to press to (doubly) confirm their signup process - hence the double opt-in term. This will then put them on your email list.

3. Regularly Clean Up Your Email Lists

Okay, so you’ve created your online list. But that also means you need to maintain it regularly. Customers and subscribers come and go, it’s a natural process and perfectly normal for business. But to keep delivery rates high, you need to clean these lists every couple of months (at least every three to every six months). The quality of your list is what matters most.

This means you’ll have to check the engagement rates with every subscriber on the list and remove the subscribers who’ve been dormant or unresponsive for too long, even after several attempts to reach them. Also, look at bounced emails and dead or false email addresses.

Bento uses a pretty robust system that regularly cleans your lists to make sure there are no spam addresses. Pair that with our filter targeting active subscribers and your open rates will see a considerable boost.

4. Make Sure Your Emails are Properly Authenticated

Email authentication is important so that email servers know you’re indeed you and that the emails you send aren’t spam.

These are some of the most common methods used for email authentication:

  • The SPF protocol (Sender Policy Framework) - this one is used to confirm your identity as a sender. It compares your (the sender’s) IP, which can be found in the DNS record of your domain, with a list of IPs that have the authorization to send from that same domain.

  • The DKIM protocol (Domain Keys Identified Mail) - this one makes sure that your email isn’t used for malicious purposes during the sending process.

  • The DMARC protocol (Domain-Based Message Authentication, Reporting & Conformance) - this one uses the two previous protocols (SPF and DKIM) to make sure sent and delivered emails are safe.

  • The BIMI protocol (Brand Indicators for Message Identification) - a recent practice in which your logo goes through several authorization procedures to make sure that it is indeed your company standing behind it. It helps for brand recognition, better email security, and better deliverability.

5. Make Sure Your Email Copy is Well Written

As I mentioned, grammar and spelling errors can also spell doom for your email (pun intended). And that’s why it’s so important to double, even triple-check your grammar in the emails you send.

Also, ensure that your emails aren’t too long and that they are concise and relevant to the interests and desires of the clients who receive them.

6. Batch Send out Your Emails

If you try and send out to your whole list at once, this triggers a lot of email clients to think it’s spam and block the email. If this happens a lot, it gets your sending IP blocked as well and all future emails are guaranteed to be sent to spam. This is a common mistake many people make and Bento is set up to prevent it.

In Bento whenever you set up an email send you need to select a batch size of emails to send at once. A default number is supplied based on the data we have for how many emails can be safely sent at once.

7. Ask Your Subscribers to Whitelist Your Email Address

You can do this by kindly asking subscribers to add your “From” name and your email address to their address book. For example, you can send them a nice prompt like this one:

“To continue receiving emails from us, we kindly ask you to add us to your address book.”

Now, there will be some people who will not know how to do this, so it’s a good idea to send a walkthrough guide for whitelisting. You can send them a short written guide, or a short video guide taking them through the necessary steps.

8. Don’t Use Deceptive Subject Lines and Spam Triggers

As we already discussed, be careful when you choose the words for your email subject line and email copy. There are certain trigger words that are famous for being troublemakers, which means they make it more likely for your email to end up in the spam folder.

What are these trigger words? Well, phrases and words like “Cash bonus”, “Earn money”, “Extra bucks/cash”, “Billions”, “Free investment”, “No risk”, “Urgent”, and so on, are some of the ones that can get you in trouble.

Of course, sometimes you can’t help but include some spam trigger words in your subject line, but here the context is key. You’ll probably be ok if you send them to personalized email lists and you already have a good sender reputation. The recipients should always be people who want to hear from you.

9. Use a Spam Checking Tool

MailTester has a really nice spam-checking tool that you can use. Spam testers are a good way to help you test how well your email address functions, and whether there are any bounced emails or emails from your address that have gone to the spam folder.

10. Proofread Your Emails

I cannot stress this enough - always proofread your emails! Proofreading means going carefully through the email text and seeing if there are any grammatical, stylistic, or spelling errors that you need to fix.

Grammar and spelling errors can also spell doom for your email (pun intended). And that’s why it’s so important to double, even triple-check your grammar in the emails you send.

Of course, there are other ways to do this apart from literally reading every email you send. That would take a lot of time and effort. Grammarly, for example, is a tool that helps you out in crafting emails with perfect punctuation and grammar. There’s even a free version you can use that’ll provide you with all the basics you need. If, however, you want to be extra careful about phrasing and word use, then I suggest you get the paid version.

If you’re crafting a particularly important email, make sure to read it out loud to yourself or to a colleague. This will help you to notice immediately if something is wrong or awkward with the structure and the tone.

Also, make sure that your emails aren’t too long, that they are concise and precise, and relevant to the interests and desires of the clients that receive them.

11. Offer Your Subscribers the “Unsubscribe” Option

There is actually a law for this, so like it or not, you have to oblige and offer your subscribers the option to unsubscribe if they want. You must offer a way for your recipients to opt out of receiving your emails should they no longer want to receive them.

Most of the time companies provide an unsubscribe option at the end of the email. Alternatively, you can offer your subscribers to go to their preference center and change their subscription choices.


Email deliverability is a huge topic that can’t be tackled in one article. But, I do hope I managed to make some basic things clear so you can prevent your emails from ending up in the spam folder too often.