Reset the root password when it is lost

I have a similar problem when the admin user tries to ssh login to a NS VM. The password is accepted but after the greeting message the shell hangs. SSH root access is enabled but obviously the root password is not set. How can I get out of this trap?

can you ssh with the root user ?

No. I lost the root password. “Admin” has administrator rights, he can set changes in the Web GUI, but the ssh login works and then the console hangs. An unprivileged user can login without problems.

ssh as an unprivileged user, then su admin and then…try to change the root password

Good idea. But then ssh hangs after entering the admin password. It is the same password I can login to the Web GUI with.

then your best chance now is to find a how to, how to reset the root password

https://wiki.centos.org/TipsAndTricks/ResetRootPassword

Thanks, Stéphane. That was the right solution. I recommend this link for resetting the root password in a Centos 7 machine:
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/sec-terminal_menu_editing_during_boot#sec-Recovering_Root_Password