Causes
- Bluetooth connection dropped or blocked — the Charge 6 syncs to the Fitbit/Google Health app over Bluetooth Low Energy. If Bluetooth is off on your phone, the tracker is out of range, or it has paired with a different phone, sync stops. Android devices in particular can silently drop a Bluetooth connection after the phone's Bluetooth cache grows or after a Do-Not-Disturb / power-saving mode kicks in
- Phone location services turned off — on Android, scanning for and connecting to a Fitbit requires the phone's Location setting to be enabled, because Fitbit uses location as part of the Bluetooth scan permission. With Location switched off, the app cannot discover or maintain the connection to the Charge 6 even though Bluetooth is otherwise on
- A hung or outdated app — the Fitbit/Google Health app itself can get into a stuck state after a poor network connection, a background update, or an old build. When the app is frozen it stops polling the tracker for new data, so steps, sleep, and heart-rate readings never appear even though the device recorded them
- Fitbit/Google service outage — sync depends not just on your phone-to-watch connection but also on Fitbit's cloud servers. During a service outage, the app may connect to the tracker but fail to push or pull data, making it look like your specific device is broken when the problem is server-wide. Fitbit has had several such outages that temporarily stopped sync for everyone
- Phone and tracker out of step after an update — after updating the Charge 6 firmware or the companion app, the two ends of the link can be temporarily out of agreement, needing a fresh handshake. Occasionally the phone's cached Bluetooth bond with the tracker goes stale and no longer matches, blocking reconnects until it is reset
- Apply Sync Now when the tracker is near and awake — sync only completes when the Charge 6 is in Bluetooth range and its screen is not in a powered-down / doze state. If the tracker's battery is critically low or it has been idle a long time, it may not respond to a sync request until it wakes
How to Fix
- Trigger a manual sync with the tracker nearby — wake the Charge 6 (tap its screen or press the side button) and bring it within a metre of your phone, then open the Fitbit/Google Health app and pull down on the Today/Home screen, or tap the sync icon to force a Sync Now. Keeping the display awake is important, because a deeply idle tracker will not answer a quiet sync request.
- Turn on Location and Bluetooth on the phone — go to your phone's Settings > Location and make sure it is enabled, then confirm Bluetooth is on. On Android this Location requirement is a hard dependency for Fitbit sync, so leaving it off is a very common silent cause of the tracker appearing to stop syncing entirely.
- Force-stop and relaunch the app — on your phone, open App settings for the Fitbit/Google Health app and tap Force stop, then reopen it. A relaunch clears any stuck sync loop in the app. If force-stop does not help, reboot your phone to reset its Bluetooth stack, which clears the stale Bluetooth cache that commonly breaks the charge/pair connection.
- Restart the Charge 6 — plug the tracker into its charger, then press and hold the side button or open Settings > Restart Device and confirm. A device restart forces a fresh Bluetooth handshake with the phone and clears any hung sync state on the tracker side. After restarting, repeat the manual Sync Now from step 1.
- Check for a service outage — if the tracker connects but data still will not sync, verify Fitbit/Google services are up (check the service status page or a quick search for recent outages). If there is an active outage, nothing you do locally will fix it — wait for Fitbit to resolve the issue and try again later. Updating the app and phone to the latest versions also picks up fixes for known sync bugs.
- Remove and re-pair the Bluetooth connection — in your phone's Bluetooth settings, forget the Fitbit (and in the app, if asked, remove the device), then re-pair it from the app's "Set Up a Device" flow. This clears the stale Bluetooth bond that can survive app force-stops and phone reboots. After re-pairing, make sure a fresh Sync Now completes successfully.
- Update firmware and app — if sync failures persist, check the Charge 6 for a firmware update (Settings > About on the tracker, or via the app's device screen) and update the Fitbit/Google Health app from your app store. Several Charge-series firmware updates have fixed recurring sync and Bluetooth issues, so running the latest build is important.
- As a last resort, reinstall the app and re-pair — back up anything you need, uninstall the Fitbit/Google Health app, and reinstall it from the store. Sign back in and re-pair the Charge 6 as a new device. A clean app install removes any corrupted local data that a force-stop and re-pair did not clear. If sync still fails across a second phone or a computer, the tracker's Bluetooth radio may be faulty — contact Fitbit/Google support for warranty service.