I was able to upload my ssh keys to pagure.io and accounts.fedoraproject.org. I can also run the following without authentication error, showing that the key itself is working:

ssh tovrstra@pkgs.fedoraproject.org 
Connection closed by 38.145.60.17 port 22

However, when I try to interact with a forked repository with Git, it complains that I have no permissions. For example, the following works:

git remote show tovrstra -n
* remote tovrstra
  Fetch URL: ssh://tovrstra@pkgs.fedoraproject.org/forks/tovrstra/rpms/packmol.git
  Push  URL: ssh://tovrstra@pkgs.fedoraproject.org/forks/tovrstra/rpms/packmol.git
  HEAD branch: (not queried)
  Local ref configured for 'git push' (status not queried):
    (matching) pushes to (matching)

Without the -n, I get:

Connection closed by 38.145.60.17 port 22
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.

Probably related to this, when I try to get the SSH url for my fork from https://src.fedoraproject.org/fork/tovrstra/rpms/packmol the page mentions that I still need to set up my SSH key:

https://i.postimg.cc/ZnKgsN8V/screenshot.png

Source Code
You need to upload SSH key to be able to clone over SSH
GIT
Pull Requests
You need to upload SSH key to be able to clone over SSH
Learn more about these different git repos.

(I tried uploading a screenshot here, did not work.)

When I follow the link to configure my SSH key, it brings me to the settings of src.fedoraproject.org, which has no SSH keys section.

I ran into this when following the pull request guide: https://docs.fedoraproject.org/en-US/package-maintainers/Pull_Request_Guide/