Resetting your AirTags may help.
Before you begin, please check the you are using uncoated CR2032 lithium 3V coin batteries. Then, try the following steps:
- Press down on the polished stainless steel battery cover of your AirTag and rotate counterclockwise until the cover stops rotating.
- Remove the cover and the battery.
- Replace the battery.
- Press down on the battery until you hear a sound. This sound means that the battery is connected.
- 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.
- Replace the cover by aligning the three tabs on the cover with the three slots on your AirTag.
- Press down on the cover.
- Rotate the cover clockwise until it stops rotating.
You can learn more about resetting your AirTags here: How to reset your AirTag - Apple Support