There are 3 possible problems, I will describe test procedure at the end
1: NO POWER To the GFCI, they will not reset without power
Tripped breaker, bad shore power, loose screw in power distribution panel (I often say many RVers have a few screws loose,, Many times these are the screws, many times a #2 square tip is a good choice, do not tighten with rig plugged in).
Bad connection in back of GFCI (See test procedure)
Second reason: Bad GFCI
Third: in this case it does reset, but immed trips.. GROUND FAULT
Likely cause, water in patio outlet Less likely, loose wire touching something it should not
Test procedure.. Remove GFCI from wall/box
Identify LOAD wires and disconnect from them, cap the wires on the GFCI
Attempt reset.. if it works you have problem 3
If not, turn off power to GFCI, Using a magic marker label the wires still connected to the GFCI as IN.. and the ones you disconnected above as OUT, this is MOST IMPORTANT do not skip this step.
Remove wire nuts and either hook on a test lamp (Small 120 volt lamp) or a volt meter, Apply power and see what the light/meter says (LIGHT or 120 volts good) DARK/zero (or very low) Bad check closer to the box.
If any connections appear burnt or damaged that's it.
NOTE USE GREAT CARE WORKING WITH LIVE WIRES.
If it turns out you have problem 3.. Ground fault...
Start with the patio outlet.. If you open it up and take a shower, Problem found, Clean, dry, replace if necessary and re-seal.
If thats dry then work your way back toward the GFCI till you find a problem,, NOTE all dead outlets are on the GFCI.
Home is where I park it!