Bitbucket Plugin not working from Heroku

Hi,
I recently developed a Bitbucket addon and for development purposes I hosted the addon from a Cloud9 server. The add-on worked perfectly. However, I recently moved the add-on to Heroku for production release and initially the add-on OAuth consumer failed to load the addon since Heroku does not provide SSL support straight out i.e. Heroku gives http sites and not https which doesn't play nice with Bitbucket's add on managers, it would seem.
I added a Heroku SSL add-on to serve my add-on via https and now when I try to load the add-on, it just times out on Bitbucket.

If I change the Add-On's URL back to the Cloud9 url and don't make any other changes, the add on works perfectly. Can you please provide info on why this is happening? Am I missing something on the Add-On dev docs?