Your USB port hardly cares what data is being transmitted, it is likely a setting in your software.
In other words, there is nothing you need to do to the USB port, you likely have to setup your software to deal with System Exclusive messages.

So we don’t have any info we can give you without knowing what software you are running.
If you are running the “Yamaha MOXF Editor Standalone/VST”, then Sysex is up and running just fine. What software are you attempting to use?

Sysex messages can be entered in the MOXF Sequencer, by placing the message as a MIDI event on a Track. Typically, by convention, System Exclusive messages are placed on Track 1...being system wide it does not matter, but the convention simply makes them easier to find.

Press [SONG]
Select a Track (we recommend [1])
Press [EDIT]
You can place the message at any Measure:Beat:Clock you desire
Set EVENT TYPE = System Exclusive
“F0” is Start of Exclusive and is entered by default... enter the message, end with “F7” End of Exclusive.
Press [F6] SET when the message is entered.