SSL peer certificate or SSH remote key was not OK

I'm testing an API that uses curl_exec php function and a CA certificate but something is going wrong and I'm a little lost.

I have configured SSL on my apache VirtualHost and looks ok ( opening https:://[myVHost]... works ).

However the API curl call give me back this message:

• SSL peer certificate or SSH remote key was not OK

I'm not very experienced with SSL so I have few ideas about the cause of that.

UPDATE:

This is the code I'm using in my cURL request, I have commented 2 lines and changes their value (look at 'TODO' line ) and in this way it is working, however this is just a work arround ...

$opts[CURLOPT_URL] = $url;
    $opts[CURLOPT_RETURNTRANSFER] = true;
    $opts[CURLOPT_CONNECTTIMEOUT] = 50;
    $opts[CURLOPT_TIMEOUT] = 100;
    $headers = array(
        'Accept: application/json',
        "User-Agent: APIXXX-PHP-Client");
    $opts[CURLOPT_HTTPHEADER] = $headers;
    $opts[CURLOPT_USERPWD] = $env->getApiKey() . ':';
    if (certificatePresent()) {

        //  $opts[CURLOPT_SSL_VERIFYPEER] = true;
        //  $opts[CURLOPT_SSL_VERIFYHOST] = 2;

        // TODO: SET IT BACK
        $opts[CURLOPT_SSL_VERIFYPEER] = 0;
        $opts[CURLOPT_SSL_VERIFYHOST] = 0;

        $opts[CURLOPT_CAINFO] = $path

      }

    curl_setopt_array($curl, $opts);

    $response = curl_exec($curl);