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  • The Cozie setting cannot be synced between the iPhone and the Apple Watch.

    • Don't worry. This can happen sometimes. Ensure the Cozie app is open simultaneously on the iPhone and the Apple Watch. Here are a few tricks on how to fix it:
    • Turn Bluetooth off and on again on the iPhone. Then try again to sync.
    • Force close the Cozie app on the iPhone and the Apple Watch (remove the app from app switcher). Then, open both apps again and try to sync the settings again.
    • Make sure you have a good and stable internet connection.
    • Uninstall the Cozie app from the iPhone and the Apple Watch. Then, install the app again on both devices.
  • When I press the sync button in the Data or Backend tab I get an "JSON error"

    • Make sure you have internet access.
    • Make sure you have a good network connection. Flakey Wi-Fi can cause this error.
    • Make sure the JSON file for the watch survey is reachable from Safari on the iPhone.
    • Make sure the watch survey's JSON file is valid and has all fields required by the Cozie specification. There are online tools available to check the JSON validity, e.g., we use JSON Formatter & Validator
    • Firewalls can cause this error.
  • Watch survey data is not logged (e.g., ws_heart_rate)

    • Make sure that the Apple Watch is connected to the iPhone.
    • Make sure that the iPhone has access to the internet.
    • Make sure there is no update for the WatchOS pending.
  • I added a new data field to be stored in the InfluxDB. However, when I submit data, it is not stored

    The first time data with a new field name is saved in the database, the database sets the data type, e.g., if you were to implement the extraction of stride length information, you could save it as ts_stride_length. If you submit the value 1.04, the value will be stored as a floating point number (float). The stride length might vary. If you happen to submit the value 1, the database would attempt to store it as an integer. It would then see that there is already a floating point number stored under ts_stride_length and reject the new value of ts_stride_length, which is then lost.

    To avoid this issue, we force-cast the type for each field name in the backend. If you let us know what type and field name you would like to add to Cozie, we can help you with this issue.

  • Push notifications from OneSignal don't show up on my device.

    • Check the correctness of the Player ID in the Cozie data tab.
    • Check the correctness of the API key.
    • Check the correctness of the information in the Backend tab and in your Python notebook.
    • If you have created your own Cozie app:
      • Check the correctness of the Player ID on
      • Make sure you created the .p12 certificate for the main identifier.
      • Try to send a test push notification from the dashboard on