Answer
This was because of erroneous coupling of GMS Anti-Virus and GMS Anti-Spam functions.
In builds 3136 and later this is no longer an issue.
See Also:
Keywords:anti-virus restricted words return message to sender
This was because of erroneous coupling of GMS Anti-Virus and GMS Anti-Spam functions.
In builds 3136 and later this is no longer an issue.
Keywords:anti-virus restricted words return message to sender