Sorry for the way I have added this; it’s because I have tried to add it to a few forums, and in some I could not add photos or videos. So, to save having to retype it all, I just copied and pasted
After assembly of the head and installation of the new cutter have you done a cutter calibration?
In a number of occasions the cutter isn’t properly installed and it will jam stuck in the cut position. And it then basically blocks the filament path.
Restart the printer, after startup before anything else, go to parameters ( 2nd option with the sliders), goto calibration and do the cutter calibration. When there are no errors with the cutter check the filament path in the toolhead. With the printer came a wire needle, remove the PTFE tube from the head, heat up the nozzle to 250°C and push the needle wire through the hole on the top. This should be fairly easy, when you feel alot of backpressure while you aren’t at the bottom of the nozzle there is a new obstruction, which needs to be solved.
Which type of filament are you using