DNS problem

[RituRaj <ritu_turu@yahoo.com>]

I have DNS problem. THe mails from our company sent
outside have started buncing with following error. It
was working till yesterday...

... while talking to smtp.pspl.co.in.:
>>> MAIL From:<username@example.com> SIZE=3535954
<<< 451 4.1.8 Domain of sender address
username@example.com does not resolve
Deferred: 451 4.1.8 Domain of sender address
username@example.com does not resolve
Warning: message still undelivered after 4 hours
Will keep trying until message is 5 days old

real username / domainame is replaced in above.
What could be the reason? I am able to send mails to
my yahoo account but do not receive any mails from
yahoo.

PLease suggest any hints...
Rituraj


		
__________________________________ 
Do you Yahoo!? 
Check out the new Yahoo! Front Page. 
www.yahoo.com