Answer
GMS has returned an error to a remote server’s EXPN command because the command was not formed correctly.
In this case, session Undefined is processing a connection from Undefined. The remote server gave the SMTP command
Undefined
GMS rejected the command with
502 Syntax error, missing space.
This problem will not cause GMS any problems. This problem is most likely to be caused by someone who is attacking your system in an attempt to find a weakness. If you wish to find out more, you will need to contact the owner of the remote system.
See Also:
- How do I contact the owner of a remote server?
- What is the SMTP EXPN command?
- What is SMTP Response Code Theory?
- How do alerts work?
- How do I contact the owner of a client?
Keywords:EXPN syntax error attack 8111