The answer to 'why is my switch not working' is that there are several common causes, including a loose connection, a broken switch, or an issue with the wiring. The symptoms may include the switch not turning on or off, flickering lights, or no power to the connected device.
To troubleshoot, first check the switch itself - make sure it's securely connected to the wall and that the screws are tight. If the switch feels loose or wiggles, that could be the problem. You can also try replacing the switch, as they can wear out over time. If the switch seems fine, the issue may be with the wiring, such as a loose connection or a break in the circuit. This is where it's best to call in a professional electrician, as working with electrical wiring can be dangerous if you're not experienced.