Cannot save Bitbucket Cloud Repository: Invalid Username and We couldn't connect to the repository errors

Update (16/04/2020)

Please follow BAM-20900 for additional information

Problem

Because of Bitbucket cloud rest api change https://developer.atlassian.com/cloud/bitbucket/bitbucket-api-changes-gdpr/
I cannot

• create and update via UI
• upload via specs

Bitbucket cloud private and public repositories if user is an owner, for teams it works.

The UI displays the following errors when performing "Test Connection":

• Invalid Username
• We couldn't connect to the repository. The details you provided were invalid.

Note: This affects all versions before 6.9.1, 6.8.3

Workaround:

Define repository as a Git or Mercurial repository

Limitations of workaround:

• Build status integration with Bitbucket Cloud isn't supported by the Git type repository
• Create plan branch when pull request is created (automatic pull request detection) isn't supported.
• Lack of easy-to-use drop downs for branch and repository selection when configuring a repository.