My airpods won't connect to my iphone.

I don't know what the problem it started when my right airpod was not charging properly it drains quickly even if I am not using it and after using I think sometimes it won't charge even after putting it back in the charging case. So I reset my airpods and it worked well but the same problem occurs several times and sometimes it's not popping up on my screen even if I am wearing the airpods already unlike before. After the last software update on my phone I tried resetting my airpods again due to the same problem and I also did try the hard reset on my iphone first it was detectable but not connecting and after resetting again it's not detectable anymore.