Change effective on 21 February 2017
A new restriction on SSL certificates for subdomains has been added that prevents users from adding subdomains to an application (e.g.
foo.bar.com) if another app owned by a different user has a matching wildcard certificate (e.g.
*.bar.com). This new restriction is now mentioned in our article that discusses rules on adding domains.
If you are trying to add a subdomain, experience this conflict, and believe this restriction should not apply to your app, please contact Support.