Answer
GMS Anti-Spam carried out a DNSBL check on the remote system. GMS Anti-Spam has been set up so that any mail or connections from servers listed in the particular DNSBL server should be rejected.
In this case, session Undefined checked the server at Undefined. The DNSBL server at Undefined responded with Undefined.
There is no problem with GMS, so no action is required by you. However, you may wish to investigate why the remote server appears in the DNSBL list.
See Also:
Keywords:DNSBL rejected 8344