Listen to the beat. A healthy clock gives an even 'tick … tock'. An uneven, limping rhythm means it is out of beat, and this is the most common reason a clock stops after it has been moved or cleaned. A clockmaker can set it in beat. On many clocks it can also be corrected by leveling the case or carefully adjusting the crutch.
Check the case is level and firm. Carpet and uneven floors let the case rock, and that takes energy from the pendulum. Shim the case until it no longer moves.
Look for obstructions. The pendulum bob must not touch the weights, the cables or the back of the case. Weights hung in the wrong positions can also stop the clock. If they differ, the heaviest usually drives the chime.
Check the winding. A weight that is fully down, or a cable that has jumped off its pulley, will stop the clock. Never force the winding key against resistance.
When to stop and call a clockmaker: if the clock stops again after being put in beat and leveled, if you hear grinding, or if the movement has not been serviced for many years. Dry, worn pivots are a mechanical fault that home adjustment cannot fix.