When Authorization code is selected, as pop-up window is displayed with the sign-in form of the OAuth 2.0 provider. The sign-in form is provided by Azure Active Directory.
1) If your browser pop-ups are disabled, then you will be prompted to enable them by the browser. After you enable them, select Authorization code again and the sign-in form will be displayed.
2) Auto login – If user is already logged into the system, then it’s get auto logged in.