As a Mac user, but not an expert linux user. Sometimes when you follow some online tutorial to teach you work out some installation or task, you may encounter an issue of ‘permission’ deny.
You may clever enough the think of ‘I not yet grant enough permission’ so then you try using a command ‘su – root’. However, if you use this first time, you may find the Terminal reply you ‘su: sorry’, which indicate your password is incorrect.
‘What?! I am the owner of my Mac and my account is admin!!!’ You end up with this anger, and double that your Mac is kidding. In fact, [ admin != root ].
The message is really telling you that the password is incorrect. It happens just because the password is empty. What you need to do is to setup the password for the root account. The command you need is ‘sudo passwd root’, set your password (please remember the password!!!). Once you set it, you can try login as root. Now you should grant the root permission.