Some errors were noticed in the CMN log file for Mail Connector. They appeared like this:
WARN CMN.logging [3] - Message Number [25] on Thread [3] from Domino (172.21.30.151:2408) to Exchange (172.21.31.31:25): A communications failure or interruption was encountered. - InvalidOperationException: The underlying socket was closed by the operating system while attempting to receive the SMTP DATA block.
Stack Trace: at QuestSoftware.CMX.API.Core.Networking.Smtp.ServerProtocol.ReceiveMessageBody(TempStream stream)
at QuestSoftware.CMX.API.Core.Networking.Smtp.Proxy.ReceiveMessageBodyAndProcess(ServerProtocol server)
This is further corroborated by errors in the Domino Log as seen in the screen shot below.
This issue is caused by there being a lack of space on the Exchange server to accept new mail. This was occurring sporadically but as the space was filled then it would occur more often till mail delivery stopped. If one of the many Exchange servers had run out of space the issue would also be the same.
Locate the Exchange server that is running out of space and make the necessary adjustments to provide more disk space. Once this is done the warnings will cease.
