Finding out that your domain or your IP has been blacklisted is Bad News with a capital ‘B’. It impacts your deliverability tremendously, takes a lot of time and energy to get off from the email blacklist, not to mention stress and costs that it might consume. It is a well-known fact that sending an email campaign is not a piece of cake, but as email still remains the most successful acquisition channel, it is essential to have a basic understanding of what is blacklist to keep your deliverability at top-notch!

If your current email marketing strategy is simply based on sending a campaign, and you are not paying enough attention to good sending practices, you might be triggering red flags, and therefore decreasing your inbox placement. This risk, however, can be reduced by implementing good sending habits.

What is email blacklist?

An email blacklist is a real-time database of emails and IPs that due to poor sending practices were identified as spammers by anti-spam organizations. Thanks to such lists email administrators have a possibility to block emails that are being sent from already black listed addresses. Basically, when you are sending an email to Izabela from let’s say, while your IP address is 123.123.123, Izabela’s mail server takes your data and scans it against those available blacklists. If or 123.123.123 IP is found on any of those blacklists, your email will land in the spam box, or it might be even rejected completely.

What are the major blacklist providers?

There is a variety of blacklists available on the internet, however, the most popular ones are maintained by companies that are specialized in doing it:
Spamhaus – they provide quite a few lists, but the SBL Spamhaus Block List is the one where legitimate senders tend to run into. It includes emails known from spam operations, sources and services. Their spam traps are often added to lists available to purchase.
Barracuda – their list was firstly built around addresses that spammed their own infrastructure. Their list is widely used by others.
Spamcop – build their list around spam traps and spam reports, and based on those they assign a reputation score to your IP address. Once your score will go below a certain threshold, your IP will be added to their blacklist.

Major businesses and email service providers use those lists, therefore you should make sure that your domain is not listed on any of those, as your inbox placement will drop significantly.

How to check if my domain is blacklisted?

The first symptom that you might notice is a big drop in your open rates, however, this doesn’t always indicate that you are on email blacklist, as it could also mean that your sender reputation is lower. The best way to check if your domain or IP is on any available publicly blacklists is to run a regular blacklist check. You won’t know if your domain is blacklisted without actually checking it yourself. Fortunately, blacklist monitoring tools are available, so you won’t have to do it manually (like Debouncer, Ultratools or Mxtoolbox). Using such makes email blacklist check smoother and quicker.

How to get off a blacklist?

What to do if you find your email via domain blacklist check? First of all, if that happens, do not panic! If you are not a spammer this is reversible! However, please remember that this is a clear indicator that there is something wrong in your email marketing, and this should be fixed asap. Most importantly try to address the reason that was the cause of your blacklisting. Next apply for ‘delisting’, (removing your IP/domain from the list), on the website of the blacklists’ owner. It is crucial to act quickly, in order to prove to ISPs that you are serious about your sender reputation. Usually, the process is pretty straightforward, if you are not a serial offender, and you fix the issue before applying for delisting.

How to avoid being blacklisted?

It is important to mention that even if you are a legitimate sender, that doesn’t intentionally send spam content, you might be still ending up on a blacklist. There are a variety of factors that may impact the possibility of getting blacklisted:

  1. Spammers are the most active senders (85% off all email sent is spam), thus you might put yourself on the spam monitoring radar if you will suddenly start sending high volumes of emails.
  2. Never ever use a purchased or rented email list! There is a very high risk that within your contacts are spam traps, and by emailing those, you are sending a clear signal to ISP that you are a spammer.
  3. Poor email list hygiene – sending emails to obsolete or invalid addresses leads to high bounce rate which is a major red flag! Spammers tend to send a mass email to randomly generated emails, therefore bounce rates can indicate that one is sending spam.
  4. Missing unsubscribe link in your message, might increase spam complaint rate – people might forget that they have previously subscribed to receive your content, so allow them to easily unsubscribe instead of pushing them to report you as spam. Spam complaint rate is another indicator that you are not a legitimate sender.
  5. Sending emails with too high frequency, and overwhelming your recipients with too many messages. Try not to send more than once per week, plus make sure that you use unique content. Avoid spam triggering words like ‘free’ ‘money-back’, caps lock, red colour in the text and overuse of exclamation marks.

You can reduce the risk of getting your email domain blacklisted by simply:

  • Only messaging people that opted in receiving your emails.
  • Adding an unsubscribe link to your message.
  • Regularly verifying and cleaning your email list from undeliverable addresses with Bouncer.
  • Segmenting your recipients, and sending only relevant and interesting content.
  • Making sure that your SPF and DKIM are set up correctly.


Wrapping up

Staying away from email blacklists won’t keep you up all night if you will follow the good sending habits in your email marketing activities. You should most definitely make sure that your domain is warmed up and set up correctly before even starting your campaign. Additionally take all the possible actions to keep both your bounce rate and your spam complaint rate super low. If your domain will land on any blacklist, remember to find the cause and fix it!