Can't publish a Hangout app (extension)

Question

I've created a Google Hangout extension app, tested it works privately etc and now I'm trying to publish it. I have followed the instructions here:

https://developers.google.com/+/hangouts/publishing

I've filled in the forms correctly, created the O-Auth client ID, filled out the consent form etc. When I tick the Make this application public tickbox and try to save, a server error message pops up along the lines of:

Server Error
Whoops! Our bad.
Please try again. If the problem persists, please let us know using the "Send feedback" link below. Thanks!
Tracking Number: XXXXXXXXXXXXXXXXXXXXXXXXX
[Send feedback]

I've checked the Chrome console - the request gets a 500 error and in the JSON response I can see:

{"message":"Developer not registered with CWS."}

I have paid the $5 one-off developer fee on the Chrome Web Store and I am the Hangout project owner. I'm not sure what I'm missing here. I need to get this published in the next 24 hours...

Any useful insights? Is there any official support forum for Google+ platform developers?

UPDATE

I was using a Google Apps account before so I've paid the developer fee on a personal account to verify me on CWS, made this account owner of the Hangout project and I still get the same message response.

I believe then that it's basically just broken. Thanks Google.