CentOS Stream 10 systems using metalink in their /etc/yum.repos.d/ configuration (the default configuration) aren't able to update or install RPMs.

This is the error:
Error: Failed to download metadata for repo 'baseos': Cannot download repomd.xml: Cannot download repodata/repomd.xml: All mirrors were tried

It was caused by an update that was pushed out during Fedora datacentre migration, during which Mirrormanager had an outage.