After trying to login in to the Plesk panel with the incorrect password as per security policy admin account locked for the 30 minutes at that we have to wait for 30 minutes to get admin account unlocked or we can unlocked the admin user from shell.
Login in to server as root user and follow the following steps.
linux@server[~]#cat /etc/psa/.psa.shadow
linux@server[~]#mysql -u admin -p adminpassword
Use the password received in the first command.
mysql> use psa;
delete from lockout where login = ‘admin’;
Now try to browse the Plesk panel with the admin user and correct password.
