I have the same issue - just had a hub and 3 buttons delivered and the one thing I wanted to do with it - send pause and play commands via http to our music system.

This does go via Node Red which handles the interaction with the music server.

The http GET request works in a local browser. The URL is http://192.168.0.17:1880/squeezer/play.

Emil, you say 'just fill in the URL' and it should be fine but it isn't. What do I have to do to get it to work?