Github ssh could not resolve hostname

Describes the cause and action for error messages.

Error Message(English)：
ssh could not resolve hostname

Resolution

GitHub - 【助けて下さい＞＜】gitにssh接続が出来ない(sourcetree)｜teratail
https://teratail.com/questions/51573

ssh: Could not resolve hostname github.comの解消 - いももちのきもち
http://toricor.hatenablog.com/entry/2017/08/15/161446

Gitlabで出るエラーに悩まされてた。 - 個人的なまとめ。
https://kosuke128.hatenadiary.jp/entry/2017/07/28/221931

ssh: Could not resolve hostname github.com: Name or service not ...
https://stackoverflow.com/questions/9393409/ssh-could-not-resolve-hostname-github-com-name-or-servic・・・

ssh: Could not resolve hostname github.com + ...
https://stackoverflow.com/questions/23817046/ssh-could-not-resolve-hostname-github-com-status-access・・・

githubへの公開鍵設定で詰まりました.md ・ GitHub
https://gist.github.com/yutokyokutyo/23ed5662f7ba2a9550ee

とあるエンジニアの備忘log: GitHub 覚え書き
http://masahir0y.blogspot.com/2013/01/github_10.html

SourceTree+GitHubで「ssh: Could not resolve hostname xxx ...
http://pixelbeat.jp/sourcetree_github_ssh_resolve_hostname/

Windowsでssh - 人生dat落ち
http://eiua-memo.tumblr.com/post/157435002150/windows%E3%81%A7ssh-hostname-%E3%81%97%E3%81%9F%E3%82%・・・