In the scenario where users cannot be added on a Windows Server because the Add User or Group button is grayed out in User Rights Assignment in Domain Controller Local Security Policy settings ...

Let us look at the procedure in detail. We will also take a look at how to add or remove Users from a Group. To add or remove Users from a Group: Open the Groups folder Select the Group Double ...

To add your user to the admin group, you would issue the command (as a user who already has full sudo privileges): sudo usermod -a -G sudo USERNAME Where USERNAME is the name of the user to be added.