Recently I was required to make cURL requests to SSL site from a website hosted on Plesk. I had perfectly written PHP cURL code snippet working on non-SSL cURL requests but on SSL I was getting following error:

Error Number:77
Error String:error setting certificate verify locations: CAfile: C:\Program Files (x86)\Parallels\Plesk\Additional\PHPSettings\cacert.pem CApath: none

After spending fifteen minutes I came to know It was Plesk Certificate Authority(CA) issue.

Symptoms:

I was receiving following error, you may receive another like this.

Resolution:

Easiest way is to download certificate from http://curl.haxx.se/ca/cacert.pem and put it in C:\\Program Files (x86)\\Parallels\\Plesk\\Additional\\PHPSettings directory.

For detailed reference: Websites are unable to make php curl requests to SSL sites