I've got ECE & CUE without sse-proxy: I can log into CUE, but I get an HTTP auth challenge for the web service. Why is this?
Content Engine's SSE endpoint is protected using the standard auth mechanisms. However, CUE and most browsers don't allow us to add auth headers or anything at all to the sse request. The SSE Proxy, however has no authentication but adds authentication requests when it makes requests to the backend(s) it has.
If ECE is not configured to let its client know where to find the proxy, ECE will fallback to it's own password protected sse stream