The answer to 'why is my electrical panel circuit overload' is that the circuit is drawing more electricity than it is rated to handle. This can be caused by a variety of issues, such as too many appliances or devices running on the same circuit, a short circuit, or a malfunctioning electrical component. Symptoms of an overloaded circuit include flickering lights, outlets that don't work, or circuit breakers that keep tripping.
If you have an overloaded circuit, the first step is to reduce the electrical load on that circuit by unplugging some devices or appliances. You can also try resetting the circuit breaker. However, if the problem persists, it's best to call a licensed electrician to diagnose and fix the issue. Trying to fix an overloaded circuit yourself can be dangerous and may lead to further electrical problems or even a fire.