Internal communications to send E-mail to each other can send and receive, in 163 the mail to send, can receive 163, 163 back to the mail is not receive, what reason is this

CodePudding user response:

Ports have open, not just on the server, include firewall,
DNS MX records have add, address right,

CodePudding user response:

reference 1/X - I - n reply:

port have open, not only is the server, include firewall,
DNS MX records have add, address right,

Check the ports are open, mx records are added, particularly strange,,,