Fedora 37 (used for dom0 in Qubes OS 4.2) has been End-of-Life since 2023-12-05. The repositories for it are moved from the releases repos to archives repo 7 days ago (see announcement). If you have manually set the update URL for Fedora repos in dom0 to a nearby mirror, please be advised that it will not have it anymore in previous URL. Since skip_if_unavailable is set to False for its repo, background refreshing of all dom0 repositories (including Qubes repos) might fail without you noticing. So revert back to metalink or update your baseurl accordingly.