Blacklisting occurs when your server's IP address or domain name is added to one or more email blacklists.
As a result, emails sent from the blacklisted server may be blocked or marked as spam by various email providers and spam filters.
For instance, you can use our blacklist check tool to check if your server is currently listed on any public blacklists.
Some common reasons why a mail server may get blacklisted include:
- Sending Spam: If your mail server is sending out a large volume of unsolicited or spam emails, it can get flagged and blacklisted by various spam detection systems.
- Compromised Account: If one or more email accounts on your mail server get compromised and start sending spam, it can lead to blacklisting.
- Virus or Malware Activity: If your mail server is infected with viruses or malware, it might be sending out malicious emails, leading to blacklisting.
- Bulk Emailing: If your server is sending out a large number of legitimate marketing (such as newsletters) without proper email authentication mechanisms, it may trigger spam filters.
- IP Address Reputation: If your server's IP address has a history of spammy behavior, it may already be on some email blacklists.