I know this is an old question, but common/confusing problem for DDP developers. I know it is the wrong forum, but there isn't a DDP development forum that I am aware of.
Access to the docs requires whitelisting of your google login user.
Either you are using the wrong user account (thus getting 404 for the docs) or because your project was on hold your user was removed from the whitelist.
You may have to restart the conversation with google DDP support which may involve revisiting your business case before giving you access to the docs...ie you may have to discuss business model before they will even give you access to the docs to enable you to start development (or update your code to be current based on latest docs).