You’ve probably put a lot of time and effort into building up your email marketing list. After all, it’s one of the most cost-effective ways of keeping your customers informed about your products, services, special offers, and other news.

That’s why it’s so disappointing to discover that your carefully crafted emails aren’t reaching all of the intended recipients. Sometimes it’s due to typos in the email addresses; other times, because those addresses have ceased to exist. And sometimes, it’s because your email address has ended up on a blacklist.

What is a blacklist?

A blacklist is a list of IP or email addresses that have been flagged as possible senders of spam. Internet service and webmail providers use blacklists to prevent their users’ inboxes from being flooded with unwanted or even malicious emails.

There are three main kinds of blacklists:

• Enterprise firewalls – private backlists created by companies to protect their IT systems.
• Private blacklists – created by ISPs and webmail providers to protect their customers.
• Public blacklists – publically available blacklists created by anti-spam companies.

How do I find out if I am on a blacklist?

Your first clue will probably be when you start to receive “message undeliverable” emails where the subject line contains words like “your IP is on our block list” or “mail from IP banned by examplewebsite.com”.

To see if you are on any of the major public blacklists, you can use free tools like MXToolBox or Multirbl.valli.org.

How did I get blacklisted, and what can I do to avoid it?

There are several ways you can unwittingly end up on a blacklist. The most common are:

Your email was hacked: Spammers will often hack into an email account and use it to send large amounts of spam. Ensure you use a strong password for your email account and enable two-factor authentication if it is available.

Your email volume changed drastically: Genuine email lists grow organically. A sudden dramatic increase in email volume can cause your email service provider to suspect you’re sending spam.

Someone is spoofing your email address: It’s possible for spammers to make their emails appear as if they came from someone else – such as you. You can help to avoid this by using a reputable email service with inbuilt security protocols that protect against email spoofing. MoreWeb’s OX email hosting includes anti-spam, antivirus, anti-phishing, one-click encryption, and other security features.

Too many people flagged your email as spam: Always be sure to obtain consent before adding people to your mailing list, and ensure that you have a working unsubscribe link in any marketing emails you send – these are legal requirements under the Unsolicited Electronic Messages Act 2007. Sending relevant, quality content to your customers will reduce the likelihood that they will report it as spam.

You sent a lot of mail directly from your email client: Personal email clients are designed for small-scale communication between people, not for marketing to large lists, and such use can send up red flags. When bulk emailing, it’s better to use a dedicated email marketing provider such as MailChimp, MailerLite, HubSpot, or Campaign Monitor.

How do I get my email address removed from a blacklist?

Fortunately, most blacklists provide the reason why they flagged you, so you can then take the necessary steps to rectify the issue. Once you’ve done that, you can approach the blacklisting site to request removal.