If you use HTTPS instead of HTTP, make sure to have corrects certificates.
If you use self signed, I will not work.
Edit this file : weathermap/lib/SimpleZabbixApi.php
Add this options in curl connection :
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);