Skype Web API "Get not supported" error on "https://pipe.skype.com/Collector/3.0/"

When experimenting with the sample code from the Microsoft getting started pages, the code from various sources (even from other questions in here) always leads me to the same error: Some internal Javascript tries to call this page and then causes the error

Element not found.

If I call this page manually, it simply says

HTTP GET not supported

Now later I saw this question that somehow seems to be related, as the guy also tries to do this with an Office365 account (same as me), but the current online documentation doesn't really make it clear for me if this is now (June 2016) any different then end of 2015.

BTW, the sample code is exactly like this one here (The mentioned bug in the question is not related, the code can be stripped down to not use jquery parameters/HTML-ID-lookup).

To make it short: is the sample supposed to work with O365? Why is it acting up so weirdly? Assuming the worst: is there an alternative to achieve connection to Skype for Business inside O365 with a lightweight Javascript or maybe even C# application? Me being sad now :-(.

UPDATE:

I found a hint on GitHub public release page that the officially support Office365. See the samples, they are now split into "on premise" and "online/o365" samples. This doesn't help me, but it makes me hope someone has an idea about my problem :-/.