“agent refused operation” when logging in with ssh keys

Copying your SSH keys to a new server is usually accomplished by

ssh-copy-id [email protected]

However, on Fedora 40, I encountered the following error after adding my keys.

username@fedora:~/.ssh$ ssh hostname.com
sign_and_send_pubkey: signing failed for RSA "/home/username/.ssh/id_rsa" from agent: agent refused operation

This appears to just be a permissions issue. To fix this, use the following commands.

chmod 700 ~/.ssh
chmod 600 ~/.ssh/*