This issue is because Indigo's Web server now uses session (cookie) information for authentication after you first enter your credentials (via HTTP Digest authentication). It isn't safe to authenticate with sessions over HTTP since the session information isn't encrypted, so Indigo's web server doesn't allow it. Unfortunately, it doesn't give a good error as to why it is failing.
If you were to access it via HTTPS then it would work, but Indigo's web server doesn't currently support HTTPS. Reflectors are always encrypted, so they always work.
We have on our feature request list to work on improving all of this and it is pretty high priority.