Fridge won't get cold on either AC or propane.

While you were away the coolant gelled from the low temperatures. If you are lucky resetting the high limit may work--but the gelling may have caused an overheating situation and caused a block in the tubing. Sometimes the blockage can be dislodged by taking the fridge out and tipping it upside down (please use violence, rolling it over several many times). I hope you get it working again soon.