PrinzEisenherz1, the post from franzstein is correct but unfortunately there is something else amiss here. The clue is that your System Diagnostic popup is showing “Powered by DarkSky”. If it were pulling data from a WU PWS then it would say “Powered by Weather Underground”.
The problem is that under certain situations – for example changing the language – the “pws” setting gets deleted and the weather service falls back to using DarkSky. The team have managed to isolate the problem and a fix is being worked on.
In the meantime, what you can do is make sure that after changing any settings via the submit button, that you then go back into the options menu and re-select the PWS in the map and then hit Submit again to store it. This should ensure that the PWS is saved. Let me know if that works in the interim.
Thanks for raising this on the forum and look out for a fix soon.