Some reasons an electrical outlet may not be working are a circuit breaker has tripped, a ground fault circuit interrupter, or GFCI, on an outlet has tripped or an outlet has burned out. In addition, if an outlet is old, it may stop working for many reasons; for example, if the wiring becomes loose. Some outlets can be switched on and off, so this kind of outlet may not be working because it is turned off.
To find out if an outlet is not working because a circuit breaker has tripped, inspect the electric panel. All the knobs on the panel may be in the correct position, but a circuit breaker for the outlet may still be tipped. Flip the knobs off and on to reset them for sure. If this fixes the problem but the circuit breaker trips again, unplug some devices, because the electrical system is overloaded.
Electrical outlets that are located near sinks are usually protected with ground fault circuit interrupters. These protectors might cause the outlets to switch off if there is a short or an overheat. If a non-operating outlet is located in a bathroom or kitchen, reset all GFCI outlets that are located in the same room. In older houses, a GFCI outlet may cause an outlet in a different room to stop working as well.