I have a Koblenz propane cooktop in my cabin and it recently developed a gas leak. Here's a video of my soap test https://youtu.be/uhKAhUsWaUY.
The manufacturer says I should use pipe dope (or tape) to fill up the treads and stop the leak but I've heard conflicting advice about the safety of this.
The pipe coming out of the back of the cooktop goes into a brass fitting and finally the hose from my propane tank screws into that. I'd be putting the pipe dope between the stove's pipe and the brass fitting.
It can get hot in this area when the burner closest to it is used for extended periods of time so whatever I use needs to be heat resistant and propane friendly.