2011 Edge M21 with Dometic RM555. Digital display flashes and beeps with red exclamation point in all modes of operation, 120v, 12v, Gas, and Aux. Doesnt do it all the time, but mostly. RV battery is good, load tested great, 13.5 volts hooked up with charger working. Propane tanks full. Good 120v source. Online research isn't offering much. Anybody ever have a similar experience.