Describes the cause and action for error messages.
Error Message(English)：
failed to connect to github.com port 443 connection refused
git clone https://XXX, but,Failed to connect to github.com port ...
https://stackoverflow.com/questions/38401307/git-clone-https-xxx-but-failed-to-connect-to-github-com・・・
Failed to connect to github.com port 443: Connection refused ...
https://stackoverflow.com/questions/54631150/failed-to-connect-to-github-com-port-443-connection-ref・・・
Can't update cocoa pods Error: Failed to connect to github ...
https://stackoverflow.com/questions/29333057/cant-update-cocoa-pods-error-failed-to-connect-to-githu・・・
Could not push--Failed to connect to github.com port 443 ...
https://stackoverflow.com/questions/41196888/could-not-push-failed-to-connect-to-github-com-port-443・・・
Failed to connect to github.com port 443: Connection refused ...
https://stackoverflow.com/questions/24873340/failed-to-connect-to-github-com-port-443-connection-ref・・・
Improve ease of configuring Git to work with corporate proxy - GitHub
https://github.com/desktop/desktop/issues/2789
Getting Started with Git and GitHub - Git - Codecademy Forums
https://discuss.codecademy.com/t/getting-started-with-git-and-github/251527
西尾泰和のはてなダイアリー
http://d.hatena.ne.jp/nishiohirokazu/comment/20160108/1452237521
Github integration issues ? IDEs Support (IntelliJ Platform) | JetBrains
https://intellij-support.jetbrains.com/hc/en-us/community/posts/360000544640-Github-integration-issu・・・