The 2x4 test
Federal rules require every opener manual to tell you to test the opener monthly. Lay a 2x4 flat on the floor in the middle of the doorway and close the door with the wall button. The door must reverse when it touches the board. Test again after any change to the force or travel settings.
If the door does not reverse, do not use the opener to close it until it is fixed. Force and travel-limit adjustment is part of opener repair.
Source: 16 CFR 1211.16, the safety instructions every opener manual must carry (eCFR)