I've searched high and low here and elsewhere and cannot find a solution which works for my problem. Accounts on CPanel Server 1 cannot send email to accounts on CPanel Server 2. The error shown by Exim on CPanel Server 1 when trying to send is: Lowest numbered MX record points to local host I've checked that the domains for the accounts on CPanel Server 2 are in /etc/localdomains -- they are. I can send mail from other (non-CPanel) servers to accounts on CPanel Server 2 with no problem. I've restarted Exim on both servers, I've rebooted CPanel Server 2, no change. This seems to have become an issue recently (last few months?), as the same procedures requiring these emails to be sent have been in place for a long time. Any ideas at all?