Top guesses,

Air in the line since this is a new install. 2-3 minutes to go the 15' of line from the tanks in front of my camper to the stove. Force the valve the stay open and bleed the air by holding a stick lighter on the thermocouple. Add a propane stove to make bleeding easier in the future.

Tank shut off. If you open a propane tank into no pressure there is a shut off valve to prevent it dumping to atmosphere. Easy to test, if you can't hear air hissing out during bleeding it is the valve. Easy to reset, just close and open the tank again.

I've been burned by the valve thing so many times I make a habit of open, close, open on fresh tank installs.

There should be a shutoff in your house line close to your tank. I also close that before changing tanks to minimize bleeding needed.