Ok,I started to print a model.  It started to print, it got a little ways done and then suddenly dislodged from the bed    and the nozzle kept moving around creating a tangled mess.  What did i do wrong?  why did it dislodge? Stopped and tried again, but this time it didn't adhere at all and the filament just moved around on its own. stopped  print.   I have the Ender3 Pro with the magnetic cover piece that goes on the pad.