@klebermo 1. please refer to the video to clean the throat https://youtu.be/cjE_SnZ_vgk. Ender-3 replaces the nozzle with a new one, which can eliminate the white residue 2. refer to the video leveling https://youtu.be/4JGLRgsLfHE 3. When the material is sent to the nozzle, the filament will be extruded as soon as it is printed. Confirm whether to change the initial Gcode , or print a random gcode file for testing