Check the fuses in the car's fuse box to see if any are blown. If a fuse is blown, replace it with a new fuse of the same amperage.
Faulty wiring
Check the wiring to the radio to see if there are any loose or damaged wires. If there are any loose wires, reconnect them. If there are any damaged wires, replace them with new wires.
Faulty Antenna
Check the antenna to see if it is damaged. If the antenna damaged or disconnected, replace or reconnect it.
Faulty Radio
If the fuse, wiring, and antenna are all in good condition, the problem may be with the radio itself. You can try disconnecting and reconnecting the radio to see if it is working. If this does not work, the radio may need to be replaced.