git【fatal: unable to access 'XXXX': Failed to connect to github.com port 443 after 21087 ms: Couldn't connect to se rver】

依次将如下两条语句复制到git中后，点击回车

git config --global --unset http.proxy
git config --global --unset https.proxy

win+r打开cmd，将ipconfig/flushdns复制，点击回车，清理DNS缓存