Provider outage
GitHub, GitLab and Bitbucket have all had multi-hour outages that block pushes, pulls, and webhook delivery. If the only copy of a repository lives with the provider that's down, your team is blocked until the provider recovers — not until you do.
Work continues from the replica
Point remotes and CI at the mirror and keep working. Nothing was lost — the replica was current as of your last push, because it's an ordinary Git repository sitting on a host that isn't down.