2004 Classic furnace

[Reg Mary]

While boondocking in the Big Horn Mts. this last May with near freezing temps at night our furnace decided to not light. It worked the first night, but not after that. I hooked up the Honda 3000 generator thinking the batteries were low, but it did not help. We did have a back up electric heater. When we got back to a campground that had electric hookup the furnace started working. Can anyone tell me what I was doing wrong?

Thanks, Reg