500 when fetching blog.intr.overt.org

About 12 hours ago, we started failing to fetch https://blog.intr.overt.org/?feed=rss2

Here's the first failure: https://gitlab.freedesktop.org/freedesktop/planet.freedesktop.org/-/jobs/45042127#L83

@philipl, this is your blog. Could you please fix the problem? 😄