Hello $@chin
Sometimes, if the service fails to start, it can prevent successful sign-in, leading to the error message you've seen. Rebooting can sometimes temporarily resolve the issue by resetting the service status.
One effective method is to boot the computer into safe mode to enable the built-in administrator account and examine the User Profile Service's status. Start by rebooting your PC into safe mode from the settings menu under "Change PC settings" and "Advanced startup." Once in safe mode, open the Command Prompt as an administrator and activate the built-in administrator account by entering net user administrator /active:yes. Log off from your current account and log in with the administrator account. Check the User Profile Service by typing Services.msc in the Run command, right-clicking on User Profile Service, and ensuring it's running and set to Automatic startup. Additionally, consider creating a new user account to see if the issue persists with a new set of user data. After troubleshooting, remember to disable the administrator account using the command net user administrator /active:no for security reasons.