HELP! Leaky inlet valve

I have a Fridgidaire FRS26R2AW5 and the water inlet valve was leaking. I replaced it (AP5671757) and the new valve has new quick connect fittings, which are much easier…except I cant get them to stop leaking. I have double and triple checked that the cuts I made to the plastic tubes are clean and straight. Connections appear to be fine, but continue to leak. Please, anyone, some advice?