No devices for "nmcli connection show "

I’m trying to set up a mail server for a Ubuntu 20.04 VPS.
I’m following this tutorial: https://linuxhint.com/install_postfix_ubuntu_1804/

However, when I reach the following, I am not getting the expected result, which is to see a list of devices and one of them must be in green:

$ sudo nmcli connection show

There is no list at all.