The WHM transfer tool is incredibly powerful. It allows one to easily migrate a domain between two servers, with zero downtime and including DNS updates.
Unfortunately at times it can go wrong. One of it’s favourite tricks is to proxy email at the end, so that if emails are still delivered to the old server, they are instead just forwarded to the new server. This will confuse you till kingdom come.
Here are some of the commands to troubleshoot. First, let’s check what Exim thinks is the true delivery location. Not the WHM UI, but Exim:
exim -bt test@example.com test@example.com router = manualmx, transport = remote_smtp host wrong-server.example.com [a.b.c.d]
Huh? But doesn’t the UI report something else? What about the command line?
# egrep ^example.com /etc/{remote,local}domains
/etc/localdomains:example.com
Ah but wait, there is more. Here it is:
# cat /etc/manualmx example.com: wrong-server.example.com
So there you have it. Also check manualmx. It’s a proxy to another host.
Now run the command again:
# exim -bt test@example.com test@example.com router = virtual_user, transport = dovecot_virtual_delivery
More information: