Garage door reverses immediately after hitting the floor, even though nothing is in the way.

Safety first: Keep people and pets clear of the door while adjusting limits.

• Inspect floor contact: Close the door and observe how it meets the floor. If the door bows or compresses the seal heavily, reduce down travel.
• Adjust down limit: Enter the Marantec travel programming mode and slightly reduce the down limit so the door just seals against the floor without excessive force.
• Check for obstructions: Remove any raised objects, mats, or debris at the threshold.
• Test safety reversal: Perform the 2x4 test to ensure the door still reverses properly when obstructed.