AirTag won’t connect

Resetting your AirTag may help. Try the following steps:

1. Press down on the polished stainless steel battery cover of your AirTag and rotate counterclockwise until the cover stops rotating.
2. Remove the cover and the battery.
3. Replace the battery.
4. Press down on the battery until you hear a sound. This sound means that the battery is connected. 
5. When the sound finishes, repeat the process four more times, removing and replacing the battery, then pressing down on the battery until you hear a sound. You should hear a sound each time you press on the battery, for a total of five sounds. The fifth sound is different from the previous four. This indicates that the AirTag is now ready to pair.
6. Replace the cover by aligning the three tabs on the cover with the three slots on your AirTag.
7. Press down on the cover.
8. Rotate the cover clockwise until it stops rotating.

You can learn more about resetting your AirTags here: How to reset your AirTag - Apple Support

If you’re still having issues connecting your AirTag, contact Apple Support.

Similar problem. Spent an hour on phone with Apple. They had me take to a Best Buy location which told me to buy a new air tag for $29. I didn’t BUT just saw a thread that said the air tags don’t like some battery brands. I switched from Duracell to a Sony and works fine now. Btw, the thread suggested trying a Panasonic.

I replaced AirTag batteries with Duracell 2032 batteries. Only Duracell batteries with the note in the package that indicates that they work with AirTags worked. Duracell 2032 batteries in packages without the note did not work, even after rubbing them with alcohol.