AirPod Pros case problem.

I have had my airpod pros a little over a year and yesterday, all of a sudden, the case and AirPods won’t work unless it is plugged in into a charger. It flashes green while it is plugged in but as soon as I unplugged it, the light turns off and the AirPods won’t pop up on my screen and they won’t respond at all. How can I fix this ?