Why is my left AirPod not working?

Why is my left AirPod not working?

After I connect and reconnect my Air left Pod does not work.

ANSWERS:

"Using your Mac you can bias which side is louder using the balance control. Are you able to hear anything in the left AirPod?

When you have it in the charger alone does it look like it’s charging?

The only thing that might mess you up is a clogged port with ear wax or the charger is not working."