Cant get email from certain domains
 

Ok dont blast me, because of my noobishness.
I have a RH9 Server running as my web/email server
Running
qmail
vpopmail

My domain expired, unknown to me :mad: ( I wasn't the person
managing it). Needless to say I got it restored,
and everything seemed ok, until I had complaints
of some users were not getting all there mail.
I checked into it and the senders are getting this error:

Router: Failed to connect to SMTP host [domain].com
because : The server is not responding. The server may be down or you may be experiencing network problems. Contact your system administrator if this problem persists.

its been a month since I restored the domain.
more than long enough for DNS propagation.
I am trying to eliminate my server as possible cause.

What to look for?

Check you MX records to make sure they exist and do resolve to your new IP address.
Does you ISP block port 25 ? If not, make sure your SMTP server is listening on port 25.

Try telnetting to you mail server on port 25 and see what it says.