getting SslHandshakeFailedError with invoking https request how debug it?

Hello
my Qt client give me SslHandshakeFailedError error's , how can i know what exactly whent wrong , i was reading about QNetworkReply::sslErrors but i have no idea how to invoke this .
more info :
i have simple application that making https request (my case facebook api) untill today every thing was working fine since today my main development pc give me this errors from ssl global error is SslHandshakeFailedError :
The issuer certificate of a locally looked up certificate could not be found
The root CA certificate is not trusted for this purpose

but when i run the code in other pc every thing is working fine , how can i know which side is blocking me if this is the problem , maybe its something else ...