Why is there no fingerprint icon when entering fingerprint on the Xiaomi 15 Ultra?

Thank you for your support for the Xiaomi product. We apologize for the inconvenience.
This issue arises when the current SIM card has been deactivated, scrapped, or is no longer recognized by the system. When such an issue occurs, the security protection mechanism of your device is automatically triggered to safeguard your personal data and privacy. Under this security protocol, features like biometric authentication, including fingerprints and facial recognition, are temporarily disabled to prevent unauthorized access to your phone.
To resolve the issue, please remove the abnormal or unrecognized SIM card and replace it with a valid one. Once you’ve successfully inserted a working SIM card, you can proceed with biometric authentication and unlock your phone using your fingerprints or facial recognition.