DEBUG: Cache is NOT active
DEBUG: try to retieve this url:
DEBUG: wp_remote_get to
DEBUG: arguments: Array ( [timeout] => 5 [user-agent] => JCI WordPress-Plugin - free Version )
DEBUG: error getting URL:cURL error 60: SSL certificate problem: unable to get local issuer certificate
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!