Cannot Get Hplip 3-21.2 Installed

I am trying to install HPLIP for my Laserjet Pro MFP M28w printer.
I have tried 3-21.2 3-19.12 and 3-16.7 with no success.

It comes to the part where it requests your password and it does not accept what I type three times and then stops. I have changed my password to a simple character version and it still does not accept what I type in.

Messages Displayed:-

ENTER ROOT/SUPERUSER PASSWORD

Please enter the root/superuser password:
error: Password incorrect. 2 attempt(s) left.
Please enter the root/superuser password:
/
error: Password incorrect. 1 attempt(s) left.
Please enter the root/superuser password:
/f-
error: Password incorrect.
error: 3 incorrect attempts. (or) Insufficient permissions(i.e. try with sudo user).
Exiting.

I am Zorin 15.3 Ultimate
I am running it as sudo.
Any suggestions would be welcome.

Kind Regards
Raymond

I am running the Ulimate Core (gnome). I did put my password in correctly and I even ran the original command as sudo.
I am running it in the terminal window.
Is there a way to put some diagnostics into a script that would give me more information about which part of the install process it is asking for my password?

I know I ma putting in the correct password and CAPS is not on and I have made my password very simple.

I really need to have this printer working. I currently have to go to Windows 10 to print.

I ran the installation as non root like the text says and it came up with the below error messages
error: Auto installation is not supported for 'unknown' distro so all dependencies may not be installed.
Please install manually as mentioned in 'http://hplipopensource.com/hplip-web/install/manual/index.html' web-site

Zorin is not in the script as a supported operating system. I did notice in my web searching that someone said that Zorin was missing and someone helped put Zorin into the script. However I dont know if having Zorin in the script would make any difference.

Can you please open a terminal and enter in

sudo -s

Then run your hplip installer normally and it should not ask you for Root password at all since you will be running from the Root Terminal.

Thread closed. Cross-posting. Missing Module libavahi-dev for HPLIP Install - #7 by carmar