The core error goes like this: SSL certificate problem, verify that the CA cert is OK.
The first thing to do is to go to JIG settings > Advanced section > SSL verify peer setting and choose the No option. If this solved the problem, please note that it's not an optimal solution and may pose a security risk. Fix your PHP installation instead. This problem usually happens on local staging environments under Windows, and chances are it works just fine on your linux hosting.
- Download this file cacert.pem and place it in your PHP installation directory.
- Edit your php.ini file and add this line, where the path should be the real path:1curl.cainfo=c:\php\cacert.pem
- Restart the web service and you are good to go.