Check the fittings /joints again. Check specifically for cracks or dents in the flare. It is possible to over tighten those joints and crack something. I did it last year with a brake line. I usually back the fittings off and retighten to make sure the fittings are aligned. Be careful to not cross thread anything, that is a sure thing for leaks. See if there is some way to bend the lines in some way to get some wiggle room out of your lines. Are you using a flaring tool that does a double flare? If you have a decent flaring tool you should be able to get there from here.

1946 1-ton Panel
1952 1-ton Comml. W/Grain Body