AirTag not reachable but it’s nearby

From the article:

What you need

• An iPhone, iPad or iPod touch with iOS 14.5 or iPadOS 14.5 or later and two-factor authentication turned on. 
• Find My turned on.
• Bluetooth turned on.
• A strong Wi-Fi or mobile connection.
• Location Services turned on: Go to Settings > Privacy > Location Services.
• To be able to use Precision Finding and to see the most accurate location for your AirTag, turn on Location Access for Find My. Go to Settings > Privacy > Location Services, then scroll down and tap Find My. Tick While Using the App or While Using the App or Widgets. Then, turn on Precise Location.

Toggle all the related services off and back on again, then try locating the AirTag once more.

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