You're gonna get answers from more experienced than me, but testing the GFCI will cause it to trip or disconnect power. It must then be reset to restore power. Are you at home or at a camp? Doesn't hurt to start over from your power connection, make sure all breakers are not tripped and in a mid way position between ON and OFF. To reset, push to off then back to on. Remove all connected loads, try again.
2005 Dodge Ram 2500 5.9L 6 Speed
16" Michelins, Hi Spec Wheels, Max Brake, Carslile Actuator, Equal-i-zer, Dill TPMS. Campfire cook.