Why can I not follow a project?
GitHub or Bitbucket requires admin permissions to add an SSH key to a project, and to add the webhook that tells CircleCI when someone pushes new code. If you’re not an admin, invite a user with permissions to CircleCI, and have them follow the project first.
For BitBucket repos you will need to look under the user or team that is the owner of the repo to be able to add it from the CircleCI ‘Add Projects’ screen.
NOTE: CircleCI currently only supports Git repositories for BitBucket. Mercurial (Hg) repositories are not supported and will not show up on CircleCI.