The gages are not always accurate, be sure there in propane in the tank.
There is also a automatic safety shut off valve, located near the main tank shut-off valve. It is wired to the propane detector. It automatically shuts off the propane, when the detector senses propane. THese electro-magnetic valves sometimes get stuck in the off position, hence no propane,
We had to replace this safety valve and the propane detector.