13 Mistakes You’re Making That Will Land Your Emails in Spam

There’s nothing worse for an e-mail marketer than having their emails land in spam.

First of all, who decides what’s spam? There are two groups:

  • The ISPs (like Yahoo! and Comcast)
  • The people on your mailing list

If the ISPs think you’re spamming, they’ll block your emails from reaching your recipients’ inbox. And even if you do make it to the inbox, but your recipients aren’t engaging, the ISPs will notice and mark your future emails are spam. Yikes!

I’ve been in the email game for a long time, and whenever a client or company comes to me with an email deliverability issue, their problem is almost always due to one of 13 common mistakes.

Learn to recognize the 13 most common mistakes that can land your email in the spam folder–and fix them quick.


1. You’ve built a bad list

If your email marketing lists are built for quantity, not quality, then you probably have a lot of people on your list who don’t even want to be there. And if they don’t want to be there, they will ignore your emails or flag them as spam, both of which will damage your deliverability.

2. You’re using a dirty list

As your email list grows, so will the number of bad addresses due to attrition, inactivity, or even simply emails that were invalid from day one due to typos.

If you keep sending this dirty list, the ISPs will think you’re spamming people who never subscribed. Clean up your list with some good list hygiene and put it on your schedule to do this on a regular basis.

3. You bought a list

While it technically might be legal to rent email lists, it’s almost certainly going to backfire. First of all, it goes against the Terms of Service for your email service provider. And more importantly, the people in these lists have no idea who you are, and will more than likely ignore you or mark you as spam. Money down the drain.

4. You’re causing list fatigue

Send the same messages and offers over and over and over again, and people will tire of hearing from you. When that happens, they will take one of three actions: flag your emails as spam, unsubscribe from them, or ignore them—which affects your business and deliverability. Focus on segmenting your lists and providing personalized content to avoid this apathy.

5. You’re sending to people who don’t care

There’s no point e-mailing people who don’t care. You’re just punishing your own KPIs.

This is particularly true when it comes to inactive subscribers who are literally dead weight on your list—weight that brings down your deliverability. Have a plan for the disengaged and inactive and put it into action so you can either get them interested again or off your list.

6. You’re sending too many emails

53% of consumers say they get too many emails from retailers. And when people get too many emails, they do one of three things: Ignore it, unsubscribe from it, or report it as spam. Test to see which frequency works best for your list. Segment so those who want to hear from you more often do, while those who want to hear from you less also get their wish.

7. You’re all about the images

Emails with too many images, and especially emails that contain only images, are sure to end up in the spam folder. Spammers use images to hide the email text, so too many can trigger the spam filters.

8. You’re being too brief

Concise and readable copy in emails is generally a good thing, especially for mobile marketing. But be too brief, and you risk looking like spam. Strike for a happy medium.

9. You’re ignoring your ESP

Your email service provider should be paying attention to what’s going on in your world, and they should want to help you improve email deliverability. Check in with them and see what concerns they might have about your email marketing program and practices.

10. You’re ignoring your sender reputation

You can’t improve email deliverability if you have a poor sender reputation—and you can’t know you have a poor sender reputation unless you’re paying attention. Run a reputation test to see what your sender reputation says about you. Do you need to take steps to improve it? Do!

11. You didn’t get authenticated

Authentication allows ISPs and corporate networks to confirm that you are who you say you are. The best-known authentication methods are SPF, DKIM and DMARC. Authenticate for an instant increase in sender reputation.

12. Your IP address got ramped up overnight

When you switch ESPs or start a new dedicated IP address, it’s imperative that you ramp up to that new IP address slowly. This gives ISPs time to get to know you under this new “name.” If you took the hare approach and not the tortoise one, your emails could be blocked as spam at the ISP level.

13. Your HTML and plaintext emails don’t match

The best ESPs automatically generate plaintext emails based on your HTML emails so that the content matches. Make sure that’s happening, because if it’s not, it’s going to trigger spam filters.