Having your email IP address or domain added to an email blocklist can seriously affect your deliverability, and therefore the profitability of your email program. This is doubly true if you’re blocklisted during one of your key selling seasons.
For those reasons, it’s important to routinely check if your brand is on any email blocklists and, if it is, to take the necessary steps to get removed. After you’re unblocked, it’s then critical to make the necessary business and process changes to ensure that you’re unlikely to end up back on a blocklist again, as it’s much more difficult to get unblocked when you’re a repeat offender.
However, before we discuss getting off a blocklist and staying off, let’s make sure we’re clear about...
What an Email Blocklist Is
Email blocklists are lists of IP addresses or domains that have been identified as sending spam and URLs that spam emails have been known to drive traffic to. These lists are maintained by anti-spam groups and independent operators, and shared with inbox providers and corporations that manage their own email servers so they can more effectively block spam.
While there are literally hundreds of email blocklists, some of the more prominent ones are:
Among those, the most impactful blocklist to a B2C email marketing program is Spamhaus, which will disrupt email sending to many of the largest consumer mailbox providers. For a B2B email marketer, blocklists like Cloudmark CSI and Proofpoint SORBS can be very disruptive.
Need help with your email campaigns and staying off blocklists? See how the experts at Oracle Marketing Consulting can help.
How Can I Find Out If I’m on an Email Blocklist?
In addition to checking directly with the major email blocklists above, here are some tools that can check if your IP address or URL has been flagged by an blocklist:
Reading the results of these tools can be confusing, as they typically check hundreds of blocklists. For example, you might discover that your company is listed by several blocklists, even though your inbox placement rate is high. That can happen because many blocklists aren’t used extensively and therefore will have little to no impact on your email program.
However, much can and should be learned from these blocklistings, as listings on small blocklists can foreshadow listings on more powerful blocklists if nothing is done. For example, a small blocklist might have you listed because of some weaknesses in your list hygiene practices. You’d be wise to address those before the problem becomes more serious and you end up on a more impactful blocklist.
How Can I Get Removed from an Email Blocklist?
Sometimes it’s as simple as just requesting that your IP address be removed, as spammers never bother to reach out to blocklist operators. Instead, spammers just move on to another IP address and domain. So, just by contacting the blocklist, you’re indicating that you’re a legitimate sender.
Other times you will need to work with the blocklist operator and convince them you’ve addressed the behavior that got you on their radar. Some brands may find this difficult to swallow. They might say to themselves, I haven’t broken the law. This is extortion! This blocklist doesn’t have the right to have my emails blocked and hurt my business.
Well, they do have the right—just like Gmail and other inbox providers have the right to block emails from senders they feel are sending malicious or unwanted email. You can either play by the rules established by blocklists and inbox providers, or accept the consequences. Those are your two choices. We recommend that you play by the rules, because they ultimately create a better inbox experience for all consumers, as well as allowing you access to your subscribers.
So, what might a blocklist operator want you to do in order to be removed? They could ask you to:
These remedies can be painful and distract you from running your email program, so we recommend trying to avoid being blocklisted in the first place. And we certainly recommend trying to avoid being blocklisted repeatedly.
Failure to correct the underlying cause of a blocklisting will lead you right back to another blocklisting, with consequences often more severe the next time. Blocklist operators typically make it harder to get removed for a repeat listing.
With that in mind, let’s answer the question…
What Causes Brands to Be Blocklisted?
Most blocklistings are due to high spam complaint rates and hitting spam traps. These two problems can also lead to inbox providers blocking your emails or routing them to spam folders instead of the inbox.
Having a complaint rate above 0.2% is one of many signs of deliverability problems ahead. Email recipients report emails as spam for a wide range of reasons, but some of the most common are:
Hitting even one spam trap can potentially lead to a blocklisting, although typically it takes multiple spam trap hits to get you in trouble. That’s because blocklist operators, as well as inbox providers, use spam traps to detect the behavior of spammers. Spam traps come in three major varieties:
Together, these spam traps identify senders who are scraping email addresses, mailing long abandoned addresses, and mailing invalid domains—all of which are hallmarks of spammers.
How Can I Keep from Being Blocklisted?
To help minimize spam complaints and reduce the risk of adding a spam trap to your email list, consider taking the following actions, which we’ve labeled as either “highly recommended” or simply “recommended” depending on the impact of the action.
Taking the following steps are critical to keeping your brand off email blocklists:
To explore ways to safely grow your subscriber base, check out our Audience Acquisition Source Ideas checklist (free, no-form download).
Taking the following steps can also help keep your brand off email blocklists, although they have less of an impact in our experience:
Some of those recommendations are harder to implement than others, and some definitely have one-time or ongoing costs associated with them. Think of these costs as insurance premiums paid against the expense of being blocklisted. Even in the best of circumstances, being blocklisted can be costly in terms of lost email marketing revenue. In the worst cases, it can be extremely costly.
New Urgency to Get Off Blocklists
During 2022, the largest and most impactful blocklist operator, Spamhaus, greatly increased their level of activity related to providing warnings about the mailing behavior of hundreds of major brands. In a statement in August, Spamhaus confirmed that their “detection techniques, rules, and signals” had changed and that their more aggressive enforcement of abusive senders “isn’t going to stop.”
If you’re one of the brands that gets one of these “informational listings,” take the warning seriously and make program improvements quickly. Spamhaus has said that failure to do so is likely to result in a full block, which would result in 50% to 70% or more of the average sender’s email volume being blocked or bounced.
When that happens, the sender’s email service provider generally halts the sender’s sending privileges to protect both the sender and the email sending platform. If the sender fails to resolve the listing quickly, ESPs have been known to permanently suspend the sender.
Whether it’s an informational listing from Spamhaus or a blocklisting from a small operator, take every listing seriously. Because if you ignore these warning signs, deliverability problems have a tendency to quietly grow larger and larger until they’re suddenly out of control and a major expense.
Need help with getting off a blocklist or ensuring you stay off blocklists? Oracle Marketing Consulting has more than 500 of the leading marketing minds ready to help you to achieve more with the leading marketing cloud, including an Email Deliverability Services team that can help you fix deliverability problems and monitor your program to avoid problems.
Talk to your Oracle account manager, visit us online, or reach out to us at CXMconsulting_ww@Oracle.com
Now thoroughly updated, this blog post was originally published on Sept. 10, 2019 by Daniel Deneweth and Chad S. White.
Daniel Deneweth heads up a team of Email Deliverability Strategic Consultants at Responsys. He shows clients how to maximize the ROI from email through improved inbox placement. Prior to Responsys, Daniel held a variety of roles at the deliverability firm Return Path. His tenure included managing the Sender Score Certified program, where he collaborated with ISPs and helped senders implement email best practices. Daniel brings this insight and in-depth deliverability knowledge to help clients maximize their inbox placement rates, and accelerate the ROI of their email channel. Follow Daniel on Twitter where he focuses on email marketing and deliverability.
Chad S. White is the Head of Research at Oracle Marketing Consulting and the author of four editions of Email Marketing Rules and nearly 4,000 posts about digital and email marketing. A former journalist, he’s been featured in more than 100 publications, including The New York Times, The Wall Street Journal, and Advertising Age. Chad was named the ANA's 2018 Email Marketer Thought Leader of the Year. Follow him on LinkedIn, Twitter, and Mastodon.