Answer
A remote system issued a HELO greeting command to GMS but did not include its name (or hostname) so GMS has rejected the command. The name of the remote system is required by the Internet Standards.
In this case session Undefined was processing a connection from the server/client at Undefined when it received the command
Undefined
so GMS responded with
Undefined
This problem is caused by a remote system which does not comply with Internet Standards. In order to resolve this issue you will need to contact the owner of the server or client at Undefined and ask them to contact their software suppliers for an updated version. It may also be a good idea to suggest that they implement a messaging server/client which implements Enhanced SMTP so that they can benefit from lower bandwidth and latency message transfers.
See Also:
- What is the SMTP HELO/EHLO clause?
- How do I contact the owner of a remote server?
- What is SMTP Response Code Theory?
- How do I contact the owner of a client?
- What are the benefits of Enhanced SMTP?
Keywords:HELO EHLO compliance RFC821 RFC2821