AN adapter fitting question

I’m having trouble with my AN NPT fittings seating into my electric fuel pump and regulator. I can only get 1-2 thread maximum engagement using two different manufacturer’s (Aeroquip & Russell) fittings. 3/8" NPT to be exact. I have ran a 3/8" NPT tap through the pumps and regulators and they seem fine. My question is there a trick to prepping the threads before assembly? Should I remove the anodizing on the fitting threads to help get a better engagement? I’m worried I won’t get a good seal when I add the teflon tape.

BTW, what fittings do you guys use?

I'm having trouble with my AN NPT fittings seating into my electric fuel pump and regulator. I can only get 1-2 thread maximum engagement using two different manufacturer's (Aeroquip & Russell) fittings. 3/8" NPT to be exact. I have ran a 3/8" NPT tap through the pumps and regulators and they seem fine. My question is there a trick to prepping the threads before assembly? Should I remove the anodizing on the fitting threads to help get a better engagement? I'm worried I won't get a good seal when I add the teflon tape.

BTW, what fittings do you guys use?