Only Git repositories are supported at this point. Other types of repositories (e.g. Mercurial, TFSVC, etc) will not show up in the repository list.

When connecting to a repository belonging to an organization on GitHub or team on Bitbucket, you must first request administrator access to the repository. Admin rights are required because App Center will register a webhook on your repository coming from the appcenter.ms domain. Depending on your organization's configuration, for GitHub repositories, the first time a member requests App Center access to that organization, an organization member with owner privileges may need to approve that request. See the GitHub-specific instructions here. It can take up to a few minutes until repositories from that organization will show up in App Center.

When connecting to a repository owned by a user, you must be the owner of the repository. If you are not the owner, you can still onboard the app to App Center build by inviting the repository owner as a collaborator to the app in App Center. The owner can then connect the repository as a source to the App Center build service.