At that temperature (if the nozzle is at that temperature?) pla is melted. Just check you can push filament through manually. Pinch the side of the extruder as if you were loading filament and try to push filament down the PTFE tube. For every cm you push in bout 3 cm of extruded filament should emerge from a 0.4mm nozzle.

Once youhave tried that and get back to I will try to help further