EX2300 cannot change root password

I have super-user rights, and go thru the motion of changing the root password, but it never changes.

When I look at the config, the secret data for the password is the same as what is in all the other switches.

When I log into the switch, as root with the known password, this is what happens:

login as: root
Keyboard-interactive authentication prompts from server:
| Password:
End of keyboard-interactive prompts from server
Access denied
Keyboard-interactive authentication prompts from server:
| Password: