Well the good news is this might NOT be an inverter issue.
You said you did not hear the transfer switch.. Question do you have AC anywhere.. outlets not powered by converter,, Air Conditioners and such.. This is the first thing to look for.. If you have no AC anywere.. You have a transfer issue or a power source issue. MOST COMMON of these when using Generator is the pair of circuit breakers on the Genny.
Now. Let's assume you DO have AC in the coach (on non-inverter powered outlets) or Air Conditioners)
Check all breakers.. There may be a 30 amp in the main panel tripped.
Now to the inverter and open the connecitons panel.. Visually inspect all connections. Any evidence of failure.. Fix. See note below.
Access 120 volt IN leads (CAREFUL DO NOT LET THEM BITE YOU) Dangerous voltage/current present.
See if a test lamp (100 watt) hooked to 120 volt leads will light IF NOT problem found,, No 120 volt to Prosine is actually the problem.
If you have power to the prosine.
Shut off all power.. Turn off switch ON THE PROSINE ITSELF (Center it, both up and down are ON) Lift 12 volt leads (negative) to remove 12 volt.
Pause. Have a cup of brew... Reconnect 12 volt lead, Restore 120 volt power. Turn switch on, And see if it's fixed itself.
Beyond that I can not assist.
NOTE: The leads on the Prosine are stranded wire.. Of course the "lines" connecting it to your motor home are romex.. They use wire nuts.
I have not had the best of luck doing that (two connections burned out, ONE on the Prosine) When they burn out.. I have the tools and skills to do a proper solder job.. That seems to work better (That's how they did it in the 1940's after all but not so common today).
Clamps work well too. But are bulkier.
Home is where I park it!