[CentOS] Centos Account Email Issue

Thu Dec 27 19:08:09 UTC 2012
Scott Adams <scott at celiac.com>


I am having an issue with email on all IP-based 
site/accounts that I set up on  CENTOS 6.3 x86_64 
standard – WHM 11.34.1 (build 5). On the server's 
main IP address domain account/site, both sending 
and receiving email works just fine, however, on 
all IP-based accounts/sites I create the email 
users can send email but not receive it, and dnsstuff.com shows:

All connections to Mailservers port 25 have 
failed. The standard port for SMTP transactions 
is 25, so your servers should be operating on 
that port. It is recommended that it be fixed in 
order for your mail service to operate properly. 
The Mail Servers that failed are: | failed message send with: 
messaging failure: Time out occurred or Remote 
server closed connection prematurely

I have tried multiple solutions but haven't been 
able to get email working properly. Any ideas would be appreciated.