Hopefully this will help someone else, when I connected my AirPods I had the same issue. They would connect but wouldn’t play anything and when I tried to play a song or make a call it froze my phone up. I saw this thread and and saw that the Apple Watch and AirPods being connected at the same time wouldn’t work. I disconnected the watch, reconnected the AirPods, then reconnected the watch. The AirPods would work, but I had to disconnect the watch every time I took the headphones out of the case. Took some investigating but I finally found the solution! No need to disconnect your watch to get the AirPods to work (at least so far no issues).
1) Update to the latest iOS on watch and phone
2) Go to Settings > General > Reset > Reset All Settings (it’s a pain because notifications and any other settings are reset to factory but luckily you don’t lose anything)
3) When the phone has restarted, connect the AirPods by holding down the button on the back, case open and headphones in the case
4) Make sure watch is connected by going into the app, connect it if it isn’t
You should be all set after those steps! The AirPods won’t freeze the phone up and the Apple Watch won’t need to be disconnected every time you use the AirPods! Hope this helps.