5353 is bonjour, which is used for the discovery. If the user types in the fmnet type url for the server and the desired file name, can they open the file?
and... perhaps a local "opener file" to save time and need for user.
Why is FMSA not running out of port 5003?
I did not try to type the url in directly - that's a great idea, and I will try it if/when this happens again.
Thanks for the pointer!
The users are opening via a local opener file. When this port failure happens on 5353 the opener file can no longer resolve the connection to the server. This is because, as Wim pointed out, 5353 is used for the discovery phase of connection. This also explains why, if a user has any files from the server open, the fault does not have any effect. If a file is open then the discovery phase is skipped over.