#MastoAdmin: If you're running the Glitch fork at 2.9.2 or later, there's an issue with DNS that prevents instances running older versions of Mastodon from communicating with your instance!
This has been successfully resolved on at least one server by flushing the DNS cache. If you run a Glitch server at version >= 2.9.2, please do that now. (The method will vary based on what server OS you're running.)