My makerbot 5th gen has worked fine for a couple of months, but suddenly it won't print parts. Was able to clear jam, now filament will load and unload fine - extrudes out fine, but when i go to print a part, it WILL print the raft, but then suddenly stops and 'air prints' when it gets to the part - it stops extruding filament.
I'm wondering if others have had this problem or have suggestions.

thanks