Recently we had added new accepted domain xyz.in in our Exchange 2010 (14.2.328.10) Server and also created associated recipient policy for the same. This domain is hosted with third party and is relaying the messages after scanning to our Exchange Server.
Now it’s seen that this relaying works perfect i.e. after sending mails from other domains like gmail, yahoo, etc. it arrives at respective user mailbox in xyz.in but suddenly stops working and sender receive message as follows:
Hello, this is the mail server on (name
of hosting server).
I am sending you this message to inform you on the delivery status of a
message you previously sent. Immediately below you will find a list of
the affected recipients; also attached is a Delivery Status Notification
(DSN) report in standard format, as well as the headers of the original
message.
<test@xyz.in> delivery failed; will not continue trying
Final-Recipient: rfc822; test@xyz.in
Action: failed
Status: 5.7.1 (delivery not authorized)
Remote-MTA: dns;[NAT WAN IP of Exchange] (NAT WAN IP of Exchange)
Diagnostic-Code: smtp;550 5.7.1 Unable to relay
X-PowerMTA-BounceCategory: relaying-issues
Also if Exchange Server is restarted after this issue, the relaying starts working again but same issue occurs after some time.
Any thought on what might be causing this?
