Failed to download metadata for repo 'fedora-modular'

I’m trying to create an SSH key and GPG key for Git using this article: Using GIT in Qubes 4 with Split SSH and Split GPG - denis zanin github
I created an AppVM by cloning the vault and I just ran sudo dnf install qubes-gpg-split # but I’m receiving this error: Failed to download metadata for repo 'fedora-modular': Cannot prepare internal mirrorlist: Curl error: Couldn't resolve host name for [Could not resolve host:]

I’m a beginner to using Qubes. Any help on solving this error would be really appreciated.

Hello and welcome to the community.

You should install it in a template.

It would be a good idea to start from here

… and to check all the links posted there.

Even before that, it is advisable to start from here

It’ll be highly rewarding to read it.