hot end going into park position

[jaimiejk72 0]

hi when i start printing it starts as normal then the hotend moves back to the parked position and filament retracts.

then i have to manually push filament back to nozzeland hit print. does anyone have any ideas on how to fix this issue.

 is it a cura relatted problem or the extruder . i also have a filament runout sensor installed and have ticked the box in advanced option.