Problem downloading tones to my Chime

Hi,I have just installed a Doorbell2 and a Chime and everything works fine.But: I am not able to choose any tone, both for bell and motion. When I choose one and press "save" a message window says "settings will be updated" (or so, my device is running in german), then for about 2 minutes there is the "chime will be updated" message and then "something is going wrong" (see the attached screen shot).I have tried this on my iPhone11, my iPad and also on my Mac and Windows device. All the same (ok, the Win device has no ability to change the tone). Any idea?Thanks,Hanno