DEBUG: Cache is active
DEBUG: CacheExpireTime: 30 minutes
DEBUG: try to retieve this url:
DEBUG: wp_remote_get to
DEBUG: arguments: Array ( [timeout] => 30 )
DEBUG: error getting URL: cURL error 28: Connection timed out after 10000 milliseconds
DEBUG: no data received: check url of json-feed

EMPTY api-answer: No JSON received - is the API down? Check the URL you use in the shortcode!