I think the 2016 models do not have a pilot, they have Direct Spark Ignition. Some things to check:
Is propane tank turned on and lines purged of air? Light stove to do that. If stove won't work perhaps a propane delivery issue.
Is red light illuminated on water heater gas switch? When water heater turned on it will try to light 3 times. If flame is not sensed after 3 attempts it will go into "lockout". To reset you must cycle the power switch back off and on again.
Is battery charged or are you plugged in to shore power? DSI heaters need 12-volts to work.
If trailer was recently de-winterized, were the water heater bypass valves fully returned to "normal" position?
A few things to check, good luck!
2014 Seneca 37TS
Toads: 2014 Ford Explorer Sport or 2013 Ford Focus ST