We've learned a little about this...
There is a function of the valve on the tank so that flow is markedly reduced if there is a damaged line. So, first step would be to check the lines under the front of the trailer to see if there is any obvious damage. Then, close the valves, purge the line by opening a burner on the stove, and then SLOWLY reopen the valve on the tank.
This MIGHT work. Didn't work for us, but it's worth a try!
We ended up having to adjust the regulator.
Let us know what you learn!