Finally finished documenting this.

I've added a mock method handler in the Slack invitation AWS API gateway to handle these false errors. They are coming from bots asking for /sitemap.xml, which didn't exist as a resource in the API definition. It now exists as an API resource and returns a 404 HTTP status code, so these errors should stop. (Try it yourself – https://slack-invitation.folio.org/sitemap.xml returns a zero-length response and no error!)

Yes – I need to document the setup and upload the code to the FOLIO infrastructure repo (in case I get run over by a bus).

Now the domain name slack-invitation.folio.org does resolve and https is happy.

Is anything more needed?

Thanks for the report, .