Auto-register is no longer working with ACE

My app was working fine in dev mode. Started the submission process for the marketplace. Went back to the dev environment a week later and all of a sudden it no longer registers:

Failed to register with host (URL to my dev instance)/ (200) The app host returned HTTP response code of 404 when we tried to contact it during installation. Please try again later or contact the app vendor. Add-on not registered; no compatible hosts detected.

I have created brand new projects and followed all of the tutorials thinking I accidentally changed something in my app. New apps do not work and generate the same error message.

This is very frustrating as we were done with the initial version of the app, going through the submission process and thought we’d be releasing our app very soon. Now we can’t even evolve it, test it or deploy it any where. We’ve also seen that we’re not the only ones this is happening to, but none of the work arounds have worked for us.

Please help!

Hi, check this one: Install event calling //install and returning 404 error on install