One AirPod flashes orange and doesn’t connect, while one is green and does.

If you have reset the AirPods and that still doesn't help, then see the 'Replace a missing AirPod or charging case' section in:

Find your lost AirPods - Apple Support

Just to be sure, is kit possible you might have mixed up your AirPods with someone else's AirPods:

If you see an alert that says "AirPods Mismatch" - Apple Support

LeBobcatt Said:

"One AirPod flashes orange and doesn’t connect, while one is green and does. [...]The AirPod: no longer connects to my phone or other devices but the other one does. The marks in the case in this image are just sharpie as I had to mark it was mine within my family sorry.[...]"

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Troubleshooting AirPods Charge:

Marking these should play no role in this.

A. A Few Links to Visit:

• Start Here: Charge your AirPods with Charging Case and Learn about Battery Life - Apple Support

• If your AirPods Won’t Charge - Apple Support

• How to Clean your AirPods and EarPods - Apple Support

B. Try the Following Tasks:

• Hold Down the Button on the case for about 15 seconds.

• Use an Apple Brand Cable - not a third party one - cool though it may look, a fabric, third-part cable would likely tear - (Apple cable's are plastic and are intended for Apple)

• Remove the AirPod from the Case, then place it back in the charger. Perhaps it need to resync with he charger.