Question: how to connect airpods to iphone connection failed?
Answer: Make sure that your iOS device has the latest version of iOS. ... 
Learn what to do if only one AirPod is working.
Open Control Center and make sure that Bluetooth is on.
Put both AirPods in the charging case and make sure that both AirPods are charging. ... 
Make sure to select your AirPods as your audio device.