Why does Withings or Garmin authorisation open the provider's app and never complete?

When the provider's own app is installed, the phone can hand the authorisation link to that app instead of keeping it in the browser, and the flow can stall there.

When the provider's own app is installed, the phone can hand the authorisation link to that app instead of keeping it in the browser, and the flow can stall there.

This only happens on devices with the provider's app installed, so it often won't reproduce on your own test phone.

• Withings: the Withings app opens and the user never returns to finish consent, so no connection is created.

• Garmin on iOS: older Garmin Connect builds opened a black page with a network connection error inside the app. Updating Garmin Connect from the App Store let the connection complete.

There is no widget or API parameter to force browser-only sign-in and skip the app handoff.