If you can’t use the fingerprint reader, make sure the Credential Manager service is set to Automatic.
1. Click on the Search icon, and type services.msc.
2. Double-click on the Credential Manager.
3. Set the startup type to Automatic.
4. Then, click on the Log On tab.
5. Select Log On As: Local System Account.
6. Tick the checkbox that says Allow service to interact with desktop
7. Save the settings, and restart your computer.
If the problem persists after following these recommendations, please back up your data and visit the nearest realme service center for further assistance.