How to fix it
Work through these in order, the most common causes come first.
Start With the Basics
Restart the app: Force-closing and reopening the companion app resolves the majority of sync issues, since it often stems from the app losing its background connection rather than any tracker problem.
Check battery level: A critically low battery can pause background syncing on any of these trackers.
Charge for at least 30 minutes before troubleshooting further.
Confirm Bluetooth is on: It sounds obvious, but a phone update or accidental toggle can silently disable Bluetooth without an obvious notification.
Diagnosing Your Specific Problem
Sync worked before but stopped suddenly: Likely a stale Bluetooth connection.
Toggle Bluetooth off and on, then restart the app.
Never synced since initial setup: Check that the tracker was fully paired, not just detected, during setup.
Redo the pairing process from the beginning.
Syncs intermittently, works sometimes: Usually a distance or interference issue.
Our picks
Products we recommend
As an Amazon Associate I earn from qualifying purchases. Picks are based on manufacturer specs, independent reviews and owner reports.
Top pickFitbit
Built-in GPS means no phone required for accurate route and pace tracking
- Built-in GPS with real-time pace
- 7-day battery (5-6 hours with GPS active)
- Google Maps and Wallet integration
- 40+ exercise modes with automatic recognition
- 50-meter water resistance
✓ Pros
- Built-in GPS means no phone required for accurate route and pace tracking
- Heart rate accuracy improved noticeably over the Charge 5 in steady-state runs
- Daily Readiness Score gives a useful go or rest signal after hard training days
- Fitbit's app remains the most polished for visualizing weekly running trends
✕ Cons
- GPS running continuously cuts battery life to 5-6 hours from the rated 7 days
- Most advanced metrics require a Fitbit Premium subscription
- Screen is small for checking pace mid-stride compared to a running watch
Garmin
Body Battery gives runners a clear number for how much they have left to tra in on
- Body Battery energy monitoring
- Connected GPS via phone
- Up to 7 days battery life
- Animated on-screen workouts
- No subscription required
✓ Pros
- Body Battery gives runners a clear number for how much they have left to tra in on
- No subscription needed to unlock any feature, unlike Fitbit or Whoop
- Comfortable, low-profile band that most testers forget they're wearing overnight
- Battery consistently lasts a full week of daily runs with connected GPS
✕ Cons
- No built-in GPS, so accurate route tracking requires carrying a phone
- Touchscreen can misregister taps mid-run when sweaty
- Smaller third-party app ecosystem than Fitbit or Garmin's own watch line
Amazfit
18-day battery means far fewer mid-training-block charging interruptions
- 18-day battery life
- 1.47-inch AMOLED display
- 120 sports modes
- Alexa built-in
- 5 ATM water resistance
✓ Pros
- 18-day battery means far fewer mid-training-block charging interruptions
- AMOLED display is bright and legible in direct outdoor sunlight
- 120 sports modes cover running, trail running, and treadmill separately
✕ Cons
- Connected GPS only, so a phone is required for accurate route mapping
- Zepp companion app is less polished than Fitbit's or Garm in Connect
- Band material shows wear faster than pricier competitors after months of sweat
FAQ
Common questions
Why did my fitness tracker suddenly stop syncing after working fine for weeks?
The most common causes are a stale Bluetooth pairing that needs to be refreshed, a companion app update that requires reopening the app or granting new permissions, or the phone's Bluetooth having been toggled off and back on in a way that broke the existing connection. Start with force-closing and reopening the app before assuming a hardware problem, since software-side sync issues are far more common than a failed tracker.
Do I need to unpair and re-pair my tracker to fix a sync issue?
Not always, but it's a reliable fix when simpler steps fail. Unpairing removes the Bluetooth connection at both the phone and tracker level, and re-pairing rebuilds it from scratch, resolving most connection-state issues that a simple app restart doesn't fix. It typically doesn't erase historical data already synced to your account, since that data lives on the manufacturer's servers, not just locally on the tracker.
Can low battery on my tracker cause syncing problems?
Most trackers, including the Fitbit Charge 6, Garm in Vivosmart 5, Amazfit Band 7, and Samsung Galaxy Fit3, reduce or pause background Bluetooth activity when battery is critically low to conserve remaining power for basic timekeeping. If sync issues coincide with a low battery warning, charge the tracker to at least 20-30 percent before troubleshooting further.
Does my phone's operating system version affect syncing?
Companion apps are built andagainst specific iOS and Android version ranges, and a very outdated phone OS can cause Bluetooth Low Energy connection issues that a manufacturer hasn't specifically patched around. Keeping both the tracker's companion app and your phone's operating system reasonably up to date reduces this risk significantly.
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