RHEL8-cannot login through GUI/terminal/ssh, but can log in through web console. Help please

Suddenly, I cannot log into my RHEL8.8 locally, even with root, through GUI or terminal or rescue mode or SSH from remote machines; but I can log into the same system with the same credentials through web console: https://mymachine.edu:9090/ without any problem.

What would be the problem of this and how to solve the problem? Any tips and suggestions are greatly appreciated. Thanks.