Answer
A message was being processed but could nto be delivered for some reason. Therefore GMS has issued a protocol error and sent a DSN to the sender of the message saying that this message has not been delivered. The script that has returned an error is SMTPEOMScript or the SMTP DLL EOM function.
In this case, session Undefined was processing a connection from Undefined and is going to reject a message apparently from Undefined to Undefined. The protocol error was
Undefined
If this is the correct result, no action is required by you. If you did not want this message to be rejected, you will need to investigate the script or DLL.
See Also:
Keywords:DSN non-delivery RFC1894 8283