aipods connection

my airpods was connected to my iphone, however, the connection is lost for the left side in less than one minute, while the right side disconnected about a few seconds later. i need to reconnect both airpods again to my iphone, it works again, but then, it disconnected again as mentioned earlier. I have follow instruction guide by Apple to reset the airpods, but the same thing happens again and again, please advise what should be done.