66% of online consumers have made a purchase as a result of an email marketing campaign they received – more than any other marketing channel. Unless you’re cool with losing that potential for revenue for your business, you should be doing everything possible to get your emails delivered to your list’s inboxes, rather than their spam folder, or worse, not delivered at all.

The fact that this list is 18 items long should tell you that there are numerous (and unbelievably simple) ways to get your sendreputation hurt or domain or IP address blacklisted by major email providers. Take a look and make sure to make any necessary changes to preserve your mailing list your send reputation (and your sanity).


1. Sending poorly designed emails – No matter how much they love you, if your customers can’t read your emails, they’ll ignore them and eventually might even mark them as spam. Ensure that you’re using responsive email templates for different devices and testing before you send.

2. Using deceptive headlines to fool filters – Avoid gimmicks at all costs. Attempting to trick filters by hashbusting (using characters to separate letters, e.g. W!n ,f.r*ee), starting emails with Re: or Fwd: to give the illusion of ongoing communication or other such tactics will only get you blocked once email providers catch on.

3. Overusing images – Some email providers default to blocking images in emails, especially unfamiliar ones with all text hidden inside images. It’s best to avoid that altogether and make your email readable in the process. If you use images, make sure the text content can stand alone if images aren’t loaded.

4. Putting large text blocks within images – Also a tactic used to game filters. Email providers are catching on to this as well and using software capable of scanning images to determine content.

5. Adding attachments to emails – A 100% definite no. If you have content for your mailing list to download, upload it to a file sharing site like Dropbox or store it on your website and include a download link, rather than adding to email itself.


7. Spamming – Not only can this land you on blacklists, it could land you in jail (maybe not jail, but it is against the law). Simply put, if persons do not give you permission to email them promoting your business, don’t email them.

8. Sending emails too frequently – Some businesses can get away with emailing customers once per day, most stick to once per week or less. Ideal frequency may vary according to your audience and email content so it’s important to find out what the threshold is and make sure you don’t go beyond. The best way to keep your mailing list happy is to disclose the typical frequency when they sign up.

9. Sending from a fake personal email – Email filters also look at the from email address used to send emails to help determine legitimacy..


10. Ignoring bounced emails – There are two types of bounced emails. Soft bounces means an email is undeliverable at that time, this may happen if the intended recipient’s mailbox is full or they are experiencing server issues. You can try resending to these people at another time. A hard bounce, however, happens when an email address is nonexistent or you have been blocked from sending to that address. Resending to these bounced mail addresses is a sign of spammy behaviour.

11. Not removing inactive subscribers – If a subscriber hasn’t opened your emails, they have requested to be unsubscribed or emails to them simply don’t get delivered, they should be removed from your list.

12. BCCing lists – Don’t send mass emails directly from your email account using the BCC feature. Use professional toolsinstead, like any from this list of email marketing services.

List Building

13. Buying lists – This is never a good idea. Even if the seller has the owner’s permission to distribute their email to get specific content (which isn’t always the case), your email will be unexpected and often unwanted, which will also put you squarely in the spam box. A small note: this not the same as renting or advertising on 3rd party lists.

14. Not verifying email addresses – Double opt-in is your friend. If a person gives you their email directly or via a paper sign-up sheet, enter it through your sign-up form instead of uploading the list so they can get an opt-in email. Otherwise, you could be sending to fake or wrong addresses.

15. Merging unrelated lists – Make separate lists based on the method used to collect emails. This way you can target specific people when necessary and track back any problems to a particular collection method. Try to segment lists and send content relevant each segment.

16. Using lists for different purposes – If persons sign up for a specific reason, don’t use their email addresses for unrelated reason.

Reputation and prevention

17. Not checking delivery statistics – Use an email marketing provider that provides details statistics of open rates and times, unsubscribes and other relevant statistics that tell you how readers are interacting with your emails preferably by domain so you can spot a problem before it is too late.

18. Not monitoring Sender Reputation – Tools like ReturnPath Senderscore can give you some insight into your current reputation and if something is off.

19. Not using blacklist checkers if you suspect something is wrong – Most blacklist checkers, like MX Toolbox are free to use. Check your domain to ensure that your reputation is kept in good standing. If you spot any discrepancies, fix it early to prevent any further negative listings.


There are many potential ways that even the most well-intentioned email marketers can end up with lower send reputation or being blacklisted. And even if there is plenty of experience in the field, there are many email deliverability myths out there. It’s important to keep updated and avoid the latest spamming tricks and continuously monitor your reputation with email providers. Overall, if you stick to honest list-building practices and provide valuable content that customers can’t wait to read, then you should be well on your way to getting all the benefits email marketing has to offer.