Functioning of cooling fan of feeder block is very important for FlashForge Dreamer 3D printer. If the fan isn't working, the extruder roller gets hot and melts the filament. Because of this, the drive gear can't feed the filament inside and filament gets rolled to the drive gear. Above figures show the present case where filament gets softer and rolled to the drive gear. 

Action Point: Make sure the cooling fan of feeder block is working. Remove the rolled out filament, let the extruder roller cool down and then start the print.