Feb 17, 2020

Email blacklist: what is it and how to avoid it?

Finding out that your domain or 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 the email blacklist, not to mention the stress and costs it may consume. It is a well-known fact that sending an email campaign is not a piece of cake. However, as email 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 don’t pay enough attention to sending practices, you may be triggering red flags, therefore decreasing your inbox placement. This risk, however, can be reduced by implementing good sending habits.

What is an email blacklist?

An email blacklist is a real-time database of email addresses and IPs that were identified as spammers by anti-spam organizations due to poor sending practices. Thanks to such lists, email administrators can block emails that are being sent from already blacklisted addresses. Basically, when sending an email to Izabela from, let’s say, [email protected], while your IP address is 123.123.123, Izabela’s mail server takes your data and scans it against those available blacklists. If yourdomain.com or 123.123.123 IP is found on any of those blacklists, your email will land in the spam box, or it may be 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 – builds their list around spam traps and spam reports, and based on those, they assign a reputation score to your IP address. Once your score goes below a certain threshold, your IP is added to their blacklist.

Major businesses and email service providers use those lists, therefore, you should ensure 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 may notice is a significant drop in your open rates, however, this doesn’t always indicate that you are on an email blacklist, as it could also mean that your sender’s 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 checking it yourself. Fortunately, blacklist monitoring tools are available, so you don’t have to do it manually (like DebouncerUltratools , or Mxtoolbox). Using such makes email blacklist checks smoother and quicker.

How to get off a blacklist?

What to do if you find your email address via domain blacklist check? First of all, if that happens, don’t panic! If you are not a spammer, this is reversible! However, please remember that this is a clear indicator that there is something wrong with your email marketing, and it should be fixed asap. Most importantly, try to address the reason that caused 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 to prove to ISPs that you are serious about your sender’s 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 essential to mention that even if you are a legitimate sender who doesn’t intentionally send spam content, you may still end 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% of all email sent is spam). Thus you may put yourself on the spam monitoring radar if you will suddenly start sending high volumes of emails.
  2. Never use a purchased or rented email list! There is a very high risk that within your contacts, there 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 a high bounce rate which is a major red flag! Spammers tend to send a mass email to randomly generated email addresses, therefore, the bounce rates can indicate that one is sending spam.
  4. Missing the unsubscribe link in your message may increase the spam complaint rate – people can 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. The spam complaint rate is another indicator that you are not a legitimate sender.
  5. Sending emails too frequently and overwhelming your recipients with too many messages. Try not to send more than one per week, plus, make sure you use unique content. Avoid spam triggering words like ‘free’, ‘money-back’, caps lock, red colour in the text, and an overuse of exclamation marks.

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

  • Only messaging people that opted in to receive 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 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 starting your campaign. Additionally, take all the possible actions to keep your bounce rate and your spam complaint rate super low. If your domain lands on any blacklist, remember to find the cause and fix it!

Line and dots
Line and dots