Hmm. I have never seen this error message before.
- What browser(s)?
- Anything else displayed in the error window? Any chance you can
share a screenshot of it?
- Any messages available in your browser's JavaScript error console?
- What URL are you using to access your Gerrit server? Is it
http://127.0.0.1/? The server's hostname?
Doh, that's exactly what this is.
This message is coming out of the SMTP client code. Your local SMTP
server is refusing to deliver a message sent by "root@localhost".
Look at the sendemail section in the configuration documentation. You
should be able to reconfigure it to be more acceptable to your local
SMTP server, or disable email sending altogether if that is the
preferred route.