Hm, strange. My Denon receiver works well with radio.de API?
btw. i see that the plugin still uses http, not https!
20:24:21.702 T:1312809728 NOTICE: [xbmcswift2] Request for "/stations/topic/" matches rule for function "show_station_categories"
20:24:21.705 T:1312809728 NOTICE: [plugin.audio.radio_de] get_categories started with category_type=topic
20:24:21.706 T:1312809728 NOTICE: [plugin.audio.radio_de] __api_call started with path=menu/valuesofcategory, param={'category': '_topic'}
20:24:21.708 T:1312809728 NOTICE: [plugin.audio.radio_de] __urlopen opening url=http://radio.de/info/menu/valuesofcategory?category=_topic
20:24:22.032 T:1312809728 NOTICE: [plugin.audio.radio_de] __urlopen HTTPError: HTTP Error 503: 503
20:24:22.034 T:1312809728 NOTICE: [plugin.audio.radio_de] String is missing: network_error
20:24:22.391 T:1425011456 ERROR: GetDirectory - Error getting plugin://plugin.audio.radio_de/stations/topic/