How to Get Off an Email Blocklist, and Stay Off

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:

IP-Based Blocklists:

• Spamhaus Block List (SBL)
• SpamCop Blocking List (SCBL)
• Barracuda Reputation Block List (BRBL)
• Cloudmark Sender Intelligence (CSI)
• Proofpoint’s Spam and Open Relay Blocking System (SORBS)
• Invaluement (ivmSIP, ivmSIP/24, and ivmURI)
• Spamhaus Exploits Block List (XBL)
• LashBack’s Unsubscribe blocklist (UBL)

Domain-Based Blocklists:

• Spamhaus Domain Block List (DBL)
• SURBL

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:

• MXToolBox's MX Lookup
• Multirbl.valli.org's Complete IP Check for Sending Mailservers
• McAfee's Check Single URL
• Cisco Talos' Reputation Lookup
• Return Path Sender Score
• 250ok blocklist Checker
• Oracle Deliverability Plus (subscription required)
• Litmus Spam Testing (subscription required)
• Email on Acid Spam Testing (subscription required)

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:

• Remove all email addresses you added after a certain date
• Send a re-permission request to all email addresses added after a certain date
• Adopt a double opt-in subscription process across some or all of your subscriber acquisition sources
• Seriously consider terminating a relationship with a partner or affiliate whose behavior directly led to the blocklisting

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.

Spam Complaints

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:

• They don’t remember signing up for emails from the brand
• They can’t easily unsubscribe
• The emails aren’t relevant to them anymore

Spam Traps

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:

1. Pristine spam traps. These email addresses are created explicitly to identify spammers. The blocklist operators who create these email addresses post them online in places where only the email scraping apps used by spammers will find them. So, if someone is emailing one of these addresses, the blocklist operator knows that the sender either scraped the address or bought a list containing the scraped address. Either way, the blocklist operator then lists the sender as a spammer.
2. Recycled spam traps. When an email address is abandoned, sometimes inbox providers recycle those formerly legitimate email addresses into spam traps years later. The logic is that only spammers would email a person who stopped using that email address so long ago.
3. Typo spam traps. Blocklist operators see it as a negative indicator of email list hygiene when brands send emails to addresses with misspelled and invalid domains like “oal.com,” “gnail.com,” “yahho.com,” and “outlok.com.” So, they use spam traps with these kinds of domains.

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.

Understand all the factors that impact email deliverability.

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. 

Highly Recommended

Taking the following steps are critical to keeping your brand off email blocklists: 

• Don’t link to disreputable websites. Links are the most critical pieces of content in your emails when it comes to blocklisting concerns. As mentioned above, linking to websites with poor reputations affects your email reputation and can get you blocklisted.
• Don’t use URL shorteners in your emails. These conceal the destination of a link and are frequently used by spammers to mask URLs. Shortening even high-reputation links makes you look like a spammer.
• Never buy email lists. You can’t buy permission, so using purchased lists automatically puts you at high risk of spam complaints. Beyond that, because for-sale email lists are often created by scraping email addresses off the internet, they tend to be full of role-based email addresses (e.g., sales@company.com), outdated and abandoned email addresses that might be recycled spam traps, and—most importantly—pristine spam traps.
• Monitor the performance of your affiliates and partners. Terminate those relationships that result in high hard bounce rates and low engagement rates.
• Use active opt-ins. Pre-checked opt-in boxes and permission grants buried inside terms and conditions are passive opt-ins that result in you adding people to your email list who often really don’t want to be there. That leads to higher spam complaints and lower engagement rates. Instead, use unchecked opt-in boxes and signup forms that are explicitly for email.
• Avoid handwritten opt-in forms. Accuracy rates on transcribing handwritten email addresses are notoriously low, which dramatically increases hard bounce rates and increases spam complaint rates, too. Adopting digital opt-in methods are best, such as referring people to a URL for email opt-ins, having them opt-in for email via SMS, or having a tablet or kiosk present for them to use for signups.   
• Avoid verbal-only email address collection methods. Verbal transcription accuracy rates aren’t much better than those for handwritten transcription. If verbal collection is taking place in a store, at an event, or another in-person venue, using a screen to show a would-be subscriber the email address that you verbally transcribed can boost capture accuracy significantly. However, if verbal collection is happening remotely via a call center, for instance, then using double opt-in confirmation is the safest option.
• Suppress chronically inactive subscribers. If a subscriber hasn’t engaged in a long time—and especially if you’ve tried and failed to reengage them—then eventually it’s best to suppress emails to them. It’s generally best to send them a re-permission email first asking them to click a link in order to reconfirm their permission. If they don’t click it, you should suppress them from future emails.

To explore ways to safely grow your subscriber base, check out our Audience Acquisition Source Ideas checklist (free, no-form download).

Recommended

Taking the following steps can also help keep your brand off email blocklists, although they have less of an impact in our experience: 

• Use double-entry address confirmation. Sometimes people mistype their email address, but it’s very rare for them to mistype it twice in a row. That’s the logic behind asking subscribers to enter their email address and then to confirm it by entering it again in a separate field. It’s a simple and very cheap way of reducing hard bounces caused by entry errors.
• Use double opt-in confirmation. This is the gold standard of email permission. By requiring new subscribers to confirm their permission by clicking a link in an opt-in confirmation request email, you can be 100% confident that the email address owner was (1) the person who entered their address in the signup form and (2) that they indeed want your marketing emails. In addition to decreasing spam complaints and increasing engagement rates, double opt-in guarantees you don’t add spam traps to your email list.
• Utilize an email address verification service. These services can help catch poorly formatted and incomplete email addresses, so they help reduce hard bounces. They can also catch some domain typos that might be typo spam traps, as well as some known spam traps that are now inactive. But email address verification services don’t help keep pristine and recycled spam traps off your list.
• Make unsubscribing simple. When subscribers have to jump through too many hoops to opt out or can’t easily find the unsubscribe link, they turn to the never-fail “report spam” button. Don’t frustrate your subscribers and force their hand. Make the unsubscribe link easy to find and your unsubscribe page easy to navigate. 

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.   

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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.