- Plesk for Linux
IP address of a server got in blacklist with the following message from owners of the blacklist:
203.0.113.2 was found to be using the following name as the HELO/EHLO parameter during connections: "localhost.localdomain"
- Hostname of the server is set as localhost.localdomain in Plesk > Tools & Settings > Server Settings.
Incorrect hostname of the server. Hostname should be Fully Qualified Domain Name, for example: example.com
- Change hostname of the server using the following article: How to change or get a server hostname on Plesk server.
- Contact blacklist owners and report that the hostname has been changed to FQDM.