cURL no longer bundles ANY CA certs; so it rejects all SSL certificates as unverifiable.

You'll need to obtain your CA's cert in order for things to work as they should:

1. Download the cURL cacert.pem file and save it to your server
2. update php.ini — add curl.cainfo = "PATH_TO/cacert.pem"
3. Or add the following and/or similar to your cURL options for each instance:

method 1:

curl_setopt($ch, CURLOPT_CAINFO, "PATH_TO/cacert.pem");
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);

method 2:

curl_setopt($process, CURLOPT_CAINFO, dirname(__FILE__) . '/cacert.pem');
curl_setopt($process, CURLOPT_SSL_VERIFYPEER, true);

More information here

cURL no longer bundles ANY CA certs; so it rejects all SSL certificates as unverifiable.

You'll need to obtain your CA's cert in order for things to work as they should:

1. Download the cURL cacert.pem file and save it to your server
2. update php.ini — add curl.cainfo = "PATH_TO/cacert.pem"
3. Or add the following and/or similar to your cURL options for each instance:

curl_setopt($ch, CURLOPT_CAINFO, "PATH_TO/cacert.pem");   
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);

More information here