Display shows “17”; door opens normally but will not close from remote, only from constant‑pressure wall button.

Safety first: Keep clear of the door while testing. Do not defeat safety sensors.

• Observe sensor LEDs during operation: Watch the receiver sensor LED while commanding the door to close. If it flickers or goes out, alignment is marginal.
• Re‑align and secure: Adjust the sensors so the receiver LED is bright and solid. Tighten brackets firmly and add additional support if they flex when the door moves.
• Check for vibration issues: Ensure the sensor wires are not pulling on the sensor when the door moves. Secure wires to the wall with clips.
• Replace receiver sensor if needed: If the LED is weak or intermittent even when aligned, replace the Marantec receiver sensor or the entire sensor pair.