When adding PHP to your IIS installation on a Windows server, and you afterwards add SSL to it, everything may work at first hand, but if you need to run some curl scripts, that accesses the server with https://, you may run into this error:
“Curl (60) SSL Certificate Problem: Unable to get local issuer certificate”
This is due to the missing CA Cert from Mozilla, that PHP needs to have in it’s SSL directory, so the fix:
1) Download “cacert.pem” from here: http://curl.haxx.se/docs/caextract.html (https://curl.haxx.se/ca/cacert.pem)
2) Save the cacert.pem to the directory on the server, where the PHP version you use, resides:
3) Add this path into the php.ini you use:
4) Run “iisreset” on a command prompt with administrative privileges 
5) Test and you’re done!