Fridge controls in AUTO
Humidity Switch in 'Normal' position
Thermostat set to 'Coldest' setting
120V AC available then 'AC' will be displayed
No 120V AC then 'LP' will be displayed
IF 'LP' and a RED X show......gas failed to ignite
How long did you wait/cool with either Mode before deciding 'not cooling'
Initial cool down on either source will take 8 hrs PLUS
Just the way absorption fridges work.
Now IF fridge has been on for longer period and NOT cooling down then could be:
Bad electric heat element
Dirty propane burner
Dirty Flue/flue baffle
Low propane pressure
Here is installation/service manual
Another manual.....might have better content