hi team

i have a user complaining that he is unable to send mail to our mailserver

<'a.anyone@domain.com'>:
Sorry, I couldn't find any host named domain.com'. (#5.1.2)

after checking the rejectlog i found

2009-05-10 10:34:57 H=(domain.com) [194.79.102.100] F=<.anyony@domain.com> rejected RCPT <a.anyone@domain.com>: Sender verify failed

------------------------------------------

please anyone help to provide a soln am stack

thank you