SSL certificate problem: unable to get local issuer certificate

GuzzleHttp\Exception\RequestException cURL error 60: SSL certificate problem: unable to get local issuer certificate (see https:// curl.haxx.se/libcurl/c/libcurl-errors.html) for https:// graph.facebook.com/v3.3/oauth/access_token

getting this error in my laravel application

I have added "cacert.pem" in my php.ini file but it didn't work :(