It’s a silly though, after updated from webGUI zpanel’s dashboard, the updated password wasn’t just working!!!
So had to google a while and found the answer- keeping it for future reference-
setzadmin -set password
Note: In “password” area type “your new password”
That’s it!
it is : setzadmin –set password
Right Path is /etc/zpanel/panel/bin/setzadmin –set your_new_password