Sonos Play1 integration failed, SmartApp removal not possible

Dear all,

unfortunately, sonos integration failed.
Under I can see that the SmartApp Sonos (Connect), if I select a device however in the mobile app and hit done, I get an error message. If I would like to remove the Smartapp, I get an error message as well. When I change the name of the Sonos device in the Sonos app, it is not updated in ST. I somehow have the feeling that the SmartApp is frozen and cannot be removed.
Do you guys have any idea how to repair that?

Best regards,