Make Sure the Audio Is Supposed to Be Coming From Your AirPods
When you listen to something, your iPhone gives you the option to change the audio output to whatever you want.
When you connect your AirPods, the audio should always come out of them, but a small error might cause your iPhone to reproduce sound from its speakers or another connected device like an AirPlay speaker instead of your AirPods.
Luckily, once your AirPods are connected, it’s easy to tell your iPhone where you want the sound to come out.
After you connect your AirPods, open the Control Center by swiping down from the top right corner of your screen (on an iPhone with Face ID) or swiping up from the bottom of your screen if you’re using an iPhone SE or an older model with a home button on front.
Next, tap the AirPlay icon in the top right corner of your screen, right below the battery. Finally, tap your AirPods’ name, and your iPhone will switch immediately.