here.The pop-up is always in response to the user that called the routine. If the user was john then the pop-up is for that user. If that user has sudo rights and types in their password the the routine (install) will run with root user permissions. If you are the user root, you don't need sudo so no pop-up would be called. You can not make a user root. That user is part of the system.
SO, I think the issue is that the "pop-up" is asking for the actual root user password, and not my-user sudo password.
To protect you from yourself.
Thus, I ran passwd again and set a dummy password, re-tested and it works. Thing is, I read that it's not a wise thing to have an actual root user enabled in Ubuntu (for some sort of safety reasons).Do as I said above to disable root password. Then make sure your account can use sudo. If you can't use sudo see the info here for a solution.
That said, how could I go about deleting/disabling the existing root account and still being able to authenticate via the "pop-up" window?