Only one AirPod is connecting to my phone what shall I do
Only one airpod is connecting when I open the lid both come up but then one disappears
Did you already try the troubleshooting mentioned in the related article from above?
If your left or right AirPod isn't working - Apple Support
In case you did and your AirPod is still not working, use the link in the article to contact Apple Support and get the AirPod replaced.