The answer to 'circuit breaker not working' is that a malfunctioning circuit breaker can be caused by a variety of issues, including overloaded circuits, short circuits, or a faulty breaker. Symptoms may include the breaker tripping repeatedly, lights flickering, or appliances not receiving power.
To troubleshoot a circuit breaker issue, first check the breaker box and reset any tripped breakers. If the breaker continues to trip, try reducing the electrical load on that circuit by unplugging appliances or turning off lights. If the problem persists, the circuit breaker may need to be replaced, which is generally a job best left to a licensed electrician.