Thanks for posting!
That email doesn’t work is expected, but the errors you are seeing are unusual. They might be due to something else in your setup.
When I try to send an invite on my test self-hosted instance, I see this error:
Jobs::HandledExceptionWrapper: Wrapped Socket::ResolutionError: getaddrinfo: No address associated with hostname
And this notice in the dashboard
Also, the failure on this one is not related to email. Do you have more info on this from /logs?