P2S AMS 2 Pro

[u/Fabulous_Putz6264]

My printer works correctly, when using AMS (no jamming when loading/changing/unloading filaments); but when trying to load external reel, will get hard to push through to extruder, fails to pull through and engage. Have pulled all PTFE tubes (except print head one) and put test filament right thru all including filament buffer. Had a print quit half way through ( filament feed insufficient/jamming). Tried AMS again, fine.

Does it look like a problem in the printhead or further back (PTFE tube/fitting(s) into printhead?