Manualmx Entry Redirection Error

I encountered a similar issue while using a transfer tool to migrate websites between three servers: Server A, Server B, and Server C (which was initially not part of the migration plan).

Initially, I migrated a website from Server A to Server B, and everything worked smoothly after the migration. There were no issues with emails, the website, or the sign-up form. However, upon reviewing the traffic on the new server, I realized that we didn’t currently require such a high VPS configuration. After discussing this with the management, we decided to downgrade the current VPS to a lower one. It’s worth noting that in Contabo, we have the flexibility to upgrade the VPS in the future, but downgrading might not be possible.

Subsequently, I configured Server C and moved the websites from Server B to Server C. After the migration, everything seemed to be working fine except for emails. This prompted me to start troubleshooting the issue between Server B and Server C, especially considering that emails worked fine during the migration from Server A to Server B.

Upon investigation, I discovered that when I shut down Server B, emails stopped working. However, when I started Server B again, email functionality was restored. While checking the mail troubleshoot in WHM, I noticed that the mail host was identified as Server B, not Server C. The entry indicated “manualmx redirection” to Server B.

Checking the /etc/manualmx file on both Server B and Server C revealed that it was empty. After 8 hours of troubleshooting, I finally identified the redirection issue on Server A in the /etc/manualmx file. The domain was redirecting to the mail host on Server B. After renaming the file, everything started working fine on Server C.