The first screenshot states ‘Unable to parse IP . Please debug’ Hence, try to login on your OpenHAB server and ensure it is getting a proper IP Address.
So what I noticed a bit after my post was that the events were still flowing in the log file. The app was working also, but the web GUI was still not working properly. I checked several tabs from the Developer Tools (Firefox), and when I was on the AdBlock part, suddenly the page got displayed. AdBlock Plus and any other plugins are disabled for the site. So this is really something weird… No idea what happened.