Sendmail Error

[Dineshwar Kumar]

Hi All,

I am using mail server on Redhat Linux 7 having Sendmail-8.11.2-14
when i am sending any mail it is successfull deliverd by getting a
mail from Mailer-Daemon that



The following addresses had permanent fatal errors -----

    (reason: 553 sorry, your envelope sender domain must exist (#5.7.1))


Sep 25 15:16:30 localserver sendmail[26990]: k8P9kSb26990:
to=kumardineshwar at gmail.com, ctladdr=root (0/0), delay=00:00:02,
xdelay=00:00:01, mailer=relay, pri=30044, relay=mail.relay.com.
[203.122.58.62], dsn=5.6.0, stat=Data format error


is any one to give me the hint how to solve it, what exacallty the problem.


Thanks,

Dinesh
New Delhi