Failed to connect to github 443

From here: GitHub - failed to connect to github 443 windows/ Failed to connect to gitHub - No Error

git config --global http.proxy http[s]://userName:password@proxyaddress:port

Where port might be 3128 and userName:password might be your windows login credentials

The reason is continuous DDoS attack ... https://status.github.com/messages

Are you behind a proxy? Check content of C:\Users\[your username]\.gitconfig and make sure proxy is configured:

[http]  
    proxy = http://yourproxy.com:8080  //change your settings here
[https] 
    proxy = http://yourproxy.com:8080  //change your settings here