The repo in Belgium does not have the 43 files (yet?)
Launching the update from the Software app returns (obviously) this error
cannot update repo ‘beid-release’: Cannot download repomd.xml: Cannot download repodata/repomd.xml: All mirrors were tried; Last error: Status code: 404 for https://files.eid.belgium.be/rpm/fedora/43/repodata/repomd.xml (IP: 212.35.97.188)
Indeed. Are you able to report this to the infrastructure team please so they can take a look? If the mirror is no longer functional, they can modify the metalink information to prevent users from being directed to it.
Downloading the metalink for BE using the command
curl "https://mirrors.fedoraproject.org/metalink?repo=fedora-debug-$releasever&arch=$basearch&country=BE"
shows that Belgium does not have any official mirrors.
Update: Apparently when installing the Belgian eID repository, it also adds this repo
[beid-release]
name=Belgian eID package archive
baseurl=https://files.eid.belgium.be/rpm/fedora/$releasever
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-BEID-RELEASE file:///etc/pki/rpm-gpg/RPM-GPG-KEY-BEID-RELEASE-2025
enabled=1
which causes the issue. There is no f43 repo and you need to set enabled=0 and everything is back to normal. I will raise this with the Belgian eID team