Describes the cause and action for error messages.
Error Message(English)：
unable to connect
gitコマンドのプロトコルをhttpsに固定する(社内環境でよくある話) - Qiita
https://qiita.com/nntsugu/items/38dc49a47d1b658325e8
npm で fatal: unable to connect to github.com: と怒られるとき - コーヒー ...
http://tassi-yuzukko.hatenablog.com/entry/2018/03/26/083406
Unable to Connect to GitHub.com For Cloning - Stack Overflow
https://stackoverflow.com/questions/16298986/unable-to-connect-to-github-com-for-cloning
Installing Stencil CLI/Framework - error unable to connect to ...
https://stackoverflow.com/questions/49782731/installing-stencil-cli-framework-error-unable-to-connec・・・
Bower Install error: Unable to connect & exit code of #128
https://stackoverflow.com/questions/25891884/bower-install-error-unable-to-connect-exit-code-of-128
bower - fatal: unable to connect to github.com
https://stackoverflow.com/questions/28361937/bower-fatal-unable-to-connect-to-github-com
Git error: fatal: unable to connect a socket (Invalid argument ...
https://stackoverflow.com/questions/496277/git-error-fatal-unable-to-connect-a-socket-invalid-argume・・・
fatal: unable to connect to github.com: が出る件 - shouhの日記
http://d.hatena.ne.jp/shouh/20140125/1390640855
npm install で fatal: unable to connect to github.com となった場合 ・ GitHub
https://gist.github.com/ikkou/11139199