GMS attempted to connect to a remote system to send an email message but the connection failed so GMS is moving on to the back-up server for this domain.
In this case, session Undefined was was processing a message to be delivered to the server Undefined (IP address Undefined). The local folder name is Undefined. The connection failed so GMS is going to attempt to connect to Undefined (FQDN Undefined with MX priority Undefined).
There is no problem with GMS, so no action is required by you. However, you may wish to investigate the problem with the remote server.
Keywords:failed connection POST 8345