I have Linux Mail Server using Exim to send email. All the while, I can send mail to the domain @domainAAA.com ( I use an alias domain name here). I suspect someone change the firewall configuration on this server and now cause us cannot send to this domain any more. Every time I will get this error below from the mail log and the email will be frozen in the mail queue.
2013-12-29 03:29:49 1Vwza1-0004y1-It ** lala@domainAAA.com F=<firstname.lastname@example.org> R=lookuphost T=remote_smtp: retry time not reached for any host after a long failure period
When I verified the email address, it can be verified.
[root@eximserver]# exim -bvs lala@domainAAA.com
The exim is install from the installer of DirectAdmin
Kindly advise how to rectify this issue and how the error happen. Because I need to find out who make the mistake and prevent this case happen in the future.