The answer to 'why is my surge protector circuit overload' is that your surge protector is likely overloaded due to too many devices plugged into it. Surge protectors have a maximum capacity for the amount of power they can handle, and if you exceed that capacity, it can cause the circuit to overload and trip.
Common signs of a surge protector overload include flickering or dimming lights, devices not powering on, or the surge protector's indicator light turning off. To fix this, you'll need to unplug some devices from the surge protector to reduce the overall power draw. If the problem persists, you may need to replace the surge protector with a higher-capacity model.