[Mailman-Users] local emails cannot receive.

[P.V.Anthony]

Hi,

I really have a very strange problem. I must have messed up somewhere.

When I create mailling lists named "support at example.com" and 
"sales at example.com", local users like user1 at example.com and 
user2 at example.com cannot receive the emails. Where else external emails 
like user at external.com receives the email.

Then I created another mailing list called "another at example.com", for 
this local and external emails accounts receive the emails.

It looks like, the name "support" and "sales" has something wrong on my 
system. I am really lost now. I do not know where to even start looking 
for the fault.

There are no email accounts with the name support at example.com or 
sales at example.com on the server.

The server is CentOS 6.3 64bit. Smtp is postfix with dovecot.

Mailman version 2.1.12.

Really need some advice. Please share a solution or suggest where to 
look for possible setting error.

P.V.Anthony