We have an Exchange 2003 and IronMail. Up until now everything was fine but from yesterday we received the follow error :
This is a delivery status notification, automatically generated by MTA xxx.xxxxx.gr on Thu, 04 Mar 2010 10:30:01 +0200 Regarding recipient(s) : firstname.lastname@example.org Delivery status : Delayed. Did not receive the expected protocol response. (ath.forthnet.gr).
We have been attempting delivery for 5 times.
Maximum delivery tries attempted. Please contact your administrator to contact the destination domain or resend your message. Delivery failed.
MTA Response :4.4.1
The original message headers are included as attachment.
The above error is not related to any particular domain meaning that we have errors with diffrent domains. Last Friday we had a new patch in IronMail ver. 6.7.2, we think that the problems may have started after the patch but we are not 100% sure.
Finally the SMTP queue in Exchange is empty and the IronMail queue is full.