cpanel: lowest numbered MX record points to local host
error
using a remote mail server while being hosted on a cpanel server. you will need to remove the domain from the localdomains file. You will then need to add the same domain to the remotedomains file.
or
rejected RCPT <user@domain.com>: lowest numbered MX record points to local host or error 451
solution
make sure the domain exist in /etc/localdomains if it does not , adding the domain should fix this error
