Here are the most popular and credible blacklists that will affect your deliverability. Some blacklists are more important than others.
If you don’t honor an unsubscribe request within a specific time, your IP address gets added to the list.Įmail service providers such as Gmail and Microsoft use these blacklists to decide what to deliver to an inbox, what to send to a spam or junk folder, and what to completely block. There are also specific email addresses set up to test a company’s unsubscribe process.
Internet service providers (ISP) work with cybersecurity companies to flag IP addresses that are guilty of this abnormal activity.
There are steps you can take to fix this now and prevent more like it in the future. Does it include the words “Sender IP” and your email address?) Then you might be asking yourself, “Is my IP address blacklisted?” Meaning the answer is yes. Have you received a bounce message like this? (Pay close attention to the type of error. The following address(es) error from remote server for RCPT TO command, host: (999.99.99.999) reason: 550 Sender IP (99.999.9.999) is blacklisted at This message was created automatically by mail delivery software.Ī message that you sent could not be delivered to one of more of its recipients.