Can't login as root

to run su and su - from a user, but after typing password, I did not get anything. Does anyone have any idea of what is going on and how to fix this? Thanks a lot. Best, shin ogino

Can't login as root

to run su and su - from a user, but after typing password, I did not get anything. Does anyone have any idea of what is going on and how to fix this? Thanks a lot. Best, shin ogino