I've been using Matter Control, Cura, and Simplify 3D. All with success, but I find different models may print better with one over the other. All of a sudden, with Cura and Simplify, my printer does not feed filament into the hot end. The motor and gear do not turn at all. Matter control works flawlessly. I am completely baffled by this! I am now in the middle of a print, but my only thought is that I lowered the extruder temp on both Cura and Simplify to 180 degrees. Is there a fail safe that won't extrude if the temp is too low? Thanks in advance for any ideas.