Geeetech

So my printer was working great yesterday. I made no changes yet now when I try to print the extruder is not extruding plastic.
If I stop the job and press extrude in the firmware, it extrudes fine but when I go back to a print job nothing??
Not sure why it only stops working during a print job. Any ideas?

This was due to extruder being too close to heat bed. Once I raised it just a hair, it worked fine. So this is resolved.