Error 406 occurs when the sensor could not be successfully linked to your account during setup. This is most commonly caused by a brief Bluetooth drop during the process, the sensor already being assigned to a different account, or the app missing the necessary permissions in the background.
Here's how to fix it:
Close the FYTA app completely and restart it.
Make sure Bluetooth is active on your smartphone and that the app has permission to use it (iOS: Settings > FYTA > Bluetooth; Android: Settings > Apps > FYTA > Permissions).
Reset the sensor: briefly remove the battery (Beam, Mini, Sphere) or press and hold the button for 10 seconds until the LED flashes red.
Hold your smartphone close to the sensor (max. 30 cm) and start the setup process again using the + in the app.
Keep the app open in the foreground throughout the entire setup.
If the error persists, reach out to us via the support chat in the app. We're happy to help.