Can't login Mobile App on XIAOMI 15 Ultra (25010PN30G)

Hi,
I can’t log into the Smart Things app.

When I click on login, the browser opens. There, I log in successfully. Then I’m redirected back to the app, but the login isn’t registered there. The app continues to prompt me to log in.

I have already uninstalled and reinstalled the app and deleted all browser data.

I can see that the login via the browser was successful under https://v3.account.samsung.com/dashboard/devices.

Somehow, the app doesn’t seem to recognize the successful login.

try changing the default browser on your Xiaomi 15 Ultra

MI Browser is not supported. I tried with edge, same result, I can log in (I can see the successful login in the browser) but the App doesn’t get the login …