Same issue. Team ID: 39RJ3NW6CT. Client ID: com.kidusberhanu.mirra. Feedback: FB25209351. The sheet appears, authentication succeeds, then "Sign Up Not Completed". No credential is returned and no request reaches our server. The public authorize endpoint returns invalid_client for this client ID, while another App ID on the same team is recognized. App Review rejected us under 2.1(a) on Oct 15 and again on Nov 3. Please apply the server-side registration repair given to GW7XA5CX69 and FRL3DTJQ62.