Curl: (60) SSL Certificate problem: Unable to get local issuer certificate Error

This problem occurs because HTTPS authentication is not configured for a trusted server. By default, curl is set to not trust any cas, that is, it does not trust any server authentication. Therefore, this is why the browser cannot access your server over HTTPS. When this problem occurs, the best way for network programmers is to specify a set of default trusted cas, provided that you have purchased certificates from these CAS.
If your content is not sensitive, a quick way is to skip the SSL check item before using curl_exec:

Curl_setopt ($ ch, curlopt_ssl_verifypeer, false );

Curl: (60) SSL Certificate problem: Unable to get local issuer certificate Error