Did you try turning the fridge off and then back on with shore power disconnected? You should hear it trying to light. If it still fails to light double check that the tank is actually on and selected and make sure you don't have air in the lines by lighting your stove/furnace or whatever else is close to the fridge.
Mine did that last trip out and turning it off and back on solved it.
2016 Jayflight 26BHS Elite
2014 F150 4x4 Super Crew, Eco-Boost, Max Tow
Bayliner Trophy 2002ff