No noise comes out of the left airpod

go to Settings > General > Accessibility and scan down the page to the volume slider for balance between left and right channels. Chances are yours is set to the right all the way and it should be in the middle for balance between both channels.

Is it only when you have both AirPods in? If you use just the left AirPod do you get any sound at all? If you don't get any sound when you just use the left AirPod, make sure the case and the AirPods are charged. If you still have problems try un-pairing and re-pairing them.

Get help with your AirPods - Apple Support

If you still have problems then take them back to where you bought them to get them exchanged.