Microsoft Authenticator stalls on adding personal microsoft account

Question

I removed my Microsoft Authenticator app registration from Security → Advanced security options and tried to re-add it via QR code. The setup gets stuck indefinitely on 'adding account' (app side) / 'continue setting up' (browser side), reproduced on two separate attempts with a fresh QR code each time, after confirming the phone's connectivity, notification, and background-app settings are all correct.