Gas leak on non threaded side of flared propane fitting

[aallgeyer]

Hi there, I'm building a propane system inside a van and I used flared connections. I'm getting 2 leaks from the side of the nut where the copper tube comes out (not the threaded/flared side). What could be a reason for this? I assume I need to redo the flare... or is there something else I missed? Additionally, how can I know my flare was done correctly?

 

[oz-plumber]

What are you using to flare the pipe with?

I hope you have some experience in gas systems in vans.
They become bombs if not done properly.