[Mailman-Users] Mailing list not receiving the messages

[Bhavin Shah]

Dear all,

I am using the MAILMAN mailing list ( Version 2.1.7) for the website since
couple of years. However, since last few days the Mailing list is not
receiving the messages. Users are getting the following error message when
it is tried to send the message to the Mailing list :

************************************************************************
This is an automatically generated Delivery Status Notification

Delivery to the following recipient failed permanently:

    iaseforum at iaseguj.org

Technical details of permanent failure:
PERM_FAILURE: SMTP Error (state 9): 550-"The recipient cannot be verified.
 Please check all recipients of this
550 message to verify they are valid."
***************************************************************************

Please help me.

Regards,

Bhavin