I had a similar problem with our Alde (in our Bowlus). Heat with propane worked fine. No heat with 120V.
Turns out the Alde wasn't getting 120V. (The pump and panel work off 12V
so the electronics will work even if no 120V.) In my case the electrical failure was from the Alde getting inadvertently unplugged
But it could have just as easily been a GFCI tripping on the outlet or a breaker tripping.
I would start by checking out the electrical circuit. An easy way to see if the Alde is receiving 120V is that a "plug" icon will appear on the screen when connected to 120V.