Does your van have a gas manifold hidden somewhere which normally incorporates 4 gas taps. Oven, Hob, Heating / Boiler and finally Fridge.
I don’t know where the manifold will be on your van but on some earlier models there was a blank drawer front next to the cutlery draw which did not have a handle. One press of the door allowed the hinged flap to drop down and expose the manifold. A second press on closing the flap secured it shut.
It is possible that the Fridge gas tap is turned off for whatever reason.
Failing that, the gas jet is blocked.
A new jet is about £10 to £12.