Lack of extrusion


Im having a situation during the printing of the pieces. Sometimes suddenly the filament get stuck in some point but I can not find the area. The shaft motor is running okay and is not getting stuck during the printing, just the filament.
Sometimes it gets stuck during the raft or during the piece. I have tried cleaning the nozzle and the extrusor but it does still happen.
Can you help me? It is a M200 Printer