Unable to use reverse-proxy with Shibboleth IDP

[Peter Schober]

* Mert Metin <mert at proximify.ca> [2019-06-07 17:26]:
> Whenever I go to, idp.example.com <http://idp.example.com/>, Chrome
> gives ERR_INVALID_RESPONSE
> When I try with Safari [...]

FWIW, I'd use 'curl -v' if I wanted to see what's going on.

What did you expect to find at http://idp.example.com/?
What resource did you configure to appear there?

> I go through logs of both Shibboleth IDP and NGINX. The IDP logs
> doesn’t show any error.

The IDP by default runs in the context /idp (unless you changed that)
so the IDP application isn't even involved in a "GET /" request.
So Shibboleth can do nothing for you here, I'm afraid.

> It looks like Tomcat or Jetty in iDP container doesn’t return a
> proper HTTP header — or response? 

Since there's no TLS involved you should have an easy time tracing
requests and responses between all those componente. Without technical
specifics how do you intend to find the source of the error (or even
what the error actually is)?

-peter