Question
How to change the mail server's domain name?
Answer
The process differs depending on whether the domain uses Plesk DNS or an external DNS server.
Go to Domains > example.com > Hosting & DNS > DNS
Look for the MX record type and open it
Set Mail exchange server to the desired domain
Note: The MX record value must have a corresponding A record.
Connect to the server via SSH
Find the domain's DNS provider
# dig +short example.com NS
ns2.he.net.
ns5.he.net.
ns4.he.net.
ns3.he.net.
ns1.he.net.Log in to the DNS provider's settings page
Set the MX record to the desired domain
