generator won't start

Hi , just freshly getting into Truck camper RV, the second trip the generator ran out of LP ad stop ,after replace the bottle with new one retart the generator it won't start. Any tips of what to look for trouble shooting? It's a 2010 CummingsonanRVQG 2500 LP model 2.5 KVD 5242B with remote start/stop. there are 12.8 v at the unit, starting switch on unit are not doing anything, Any help? Thanks