Your water heater should run on propane, electric, or both. There should be switches to turn on both the gas and the electric located on the inside of your trailer. On the water heater itself, behind the outside access panel, there are two black reset buttons. You can try pushing those. Also on the outside is a switch for the electric side of the water heater. This switch must be on for the electric side of the heater to work. It’s a little black toggle switch that says on and off located in the left bottom.
I hope that helps!