why does left or right air pod operate but not together.

Hello kjdubois,

Thank you for reaching out to Apple Support Communities, and we'll be happy to help in any way we can. We understand you're having issues with your AirPods working at the same time. Were one of the AirPods replaced? If so, check out the steps listed here to set up your replacement AirPod to pair with the other: Set up your replacement AirPods or charging case

Also, when this occurs does the AirPod that isn't working show a red exclamation mark on your iPhone?

We hope this helps.

Cheers!