Hey! 
A few weeks ago I started working on a project and uploaded some code to test it via Heroku. Used one of my private key registrations to register the project but now it disappeared from my actives sites. 
Otree shows the name of the app under "Other sites" (already disconnected and reconnected heroku) and I can register it again, but it mentions that the same app is alrady registered and it would cost me another key. Any idea on what happened?

Have not deleted the App in heroku and was just planning to update the code via oTreehub, which now is not possible anymore.

If you re-register the same app it won’t cost another registration key. And if there are any issues you can send me an email, I’ll give you more keys.

If you re-register the same app it won’t cost another registration key. And if there are any issues you can send me an email, I’ll give you more keys.

Amazing! Thanks a lot for the quick reply & help Chris. Highly appreciated!