Comment 2 for bug 1998260

As per MM, this is due to a bug that's been fixed in Juju 2.9.36 (LP:1993758) where it selects the charm built for the wrong series. You'll want to upgrade to the charm with the right series, in your case, r34 per the `juju info` output provided.

It can also be seen that a unit is stuck and not upgrading, running `juju resolved --no-retry` once and wait until you see:

| juju.worker.uniter.charm bundles.go:78 downloading ch:amd64/focal/autocert-34 from API server

You may need to re-run the `resolved --no-retry` a second time.