Extruder Stepper not Running

Hi Guys!
About 2 months ago I came across an issue which has grown. A few times after startup and preheat (yes the hotend had reported 200 degrees preheat for PLA) when I tried to extract material the stepper wouldn't run. the hotend isn't jammed as I can manually feed pla through, sometimes after being left on for a while the stepper would allow me to extrude but at the moment it is not working at all! I was wondering if you could give me some insight or have any answers for this issue, I was order number 1446

Cheers