/root# whoami
root
/root# who -u
root     tty1         2025-05-21 10:57  old      3377748
root     pts/0        2025-05-27 09:59   .        706587 (87.242.189.57)
root     pts/1        2025-05-27 10:02 01:21      706822 (87.242.189.57)
/root#

/misc/cyber/securityp/practical# sudo passwd -l labuser1
passwd: password changed.
/misc/cyber/securityp/practical# sudo passwd -u labuser1
passwd: password changed.
/misc/cyber/securityp/practical# su - labuser1
labuser1@mail:~$ exit
logout

Password:
su: Authentication Failure