Error: Failed to synchronize cache for repo 'updates' [closed]
I just ran into this as well. Adding the verbose flag showed the $releasever wasn't set in the url. Check this yourself with dnf update -v
Look for these lines in the output:
Cannot download 'https://mirrors.fedoraproject.org/metalink?repo=fedora-$releasever&arch=x86_64': Cannot prepare internal mirrorlist: file "repomd.xml" was not found in metalink. Error: Failed to synchronize cache for repo 'fedora'I fixed the issue with dnf clean all && dnf update --releasever=25.This overrides the $releasever with the one you supply. After that, I was able to update and install rpms again.