Github email is already in use

Describes the cause and action for error messages.

Error Message(English)：
email is already in use

Resolution

validateUsername() reports 'Users is already in use' when ... - GitHub
https://github.com/colinskow/ng-superlogin/issues/10

[ERROR] user#signup (ActiveRecord::RecordInvalid ... - GitHub
https://github.com/mysociety/alaveteli/issues/4947

Bypass social signup for existing account ・ Issue #1149 ... - GitHub
https://github.com/pennersr/django-allauth/issues/1149

7日目: github.comはuser.emailをみてauthorが誰か判定しています（user ...
http://kimikimi714.hatenablog.com/entry/2013/12/07/7%E6%97%A5%E7%9B%AE%3A_github_com%E3%81%AFuser_em・・・

Admin Authentication API Errors | Firebase
https://firebase.google.com/docs/auth/admin/errors

GitHub - Contributor count still 1? - Stack Overflow
https://stackoverflow.com/questions/35027655/github-contributor-count-still-1

Unable to create Samsung account - email already in use!? - General ...
https://community.smartthings.com/t/unable-to-create-samsung-account-email-already-in-use/102830

can't add users to webid | WeBid Support
http://www.webidsupport.com/forums/index.php?threads/cant-add-users-to-webid.10179/

“Username or password is incorrect” is bullshit | Hacker News
https://news.ycombinator.com/item?id=15986217