I have run into this issue when I was trying to configure a Laravel 5.2 application to send emails using Mailgun. I got an exception like this, when I was trying to send an email:
cURL error 60: SSL certificate problem: unable to get local issuer certificate
To solve this issue, you have to get a local certificate, and specify it’s location in the
Download the certificate
You can download the certificate from this url: http://curl.haxx.se/ca/cacert.pem. I saved it to the root directory of my PHP installation, but it can be anywhere.
Specify the certificate’s location in php.ini
php.ini file, specify the location of this certificate by setting (of course, using your actual path to the certificate):
curl.cainfo = C:\Software\php-7.0.2-x86\cacert.pem
Restart Apache and you are done.