By default, the MSMQ transport uses the local machine name, taken from Environment., as the originator and reply-to address in messages. Windows can use NETBIOS to connect to the destination machine. Some deployment environments require the use of Fully Qualified Domain Names (FQDN) to route messages correctly. The most common scenario is routing between machines in different domains.
To use the FQDN, override the machine name
Routing
The routing configuration and any explicit queue destinations will also need to use the FQDN.