Sometimes you can also try flipping the hose. Meaning the one that went to the tank put it on the pump.
I usually get two wrenches and snug them down. One on the fitting and one of the hose end. If you flip the hose and the same point still has issue, more than likely the fitting is the culprit. Not to say a fitting couldn't be machined defectively, after all these parts are mass produced. I don't test fittings beyond a simple visual.
The larger -6 fittings can take a little more TQ than the smaller -4's. Feed hose is -6, pressure is -4
If you tighten them to a point you feel it should seal and it doesnt, don't go any further and get in touch with me for a replacement fitting. Going further will break both fittings.