I have a system I use to publish my videos according to a schedule, as well as manage the video data (tags, descriptions etc).
This system uses the PHP client library to access my YouTube account via a service account. My YouTube account is an old account (pre google buying youtube) and is hung onto the side of my main google account, thus accessing it requires impersonating it, since my main account has no videos.
I managed to work out how to do this (See: Granting permanent access for youtube account through Youtube API) after a lot of reading and testing and stumbling around.
Now, this has stopped working. Attempting to authenticate with the impersonate address included yields an unauthorized_client error. Not including it works, but like I said, doesn't return any videos.
I've read things suggesting I now need to give access to this account.
In console.developers.google.com/permissions/serviceaccounts I've added it to the permissions as an owner and Service Account Actor, but this has done nothing. I have also enabled Google Apps Domain Wide Delegation for no result.
Other documentation suggests I need to enter the Admin Console at admin.google.com to authorize the account, but I cannot access this page since it apparently requires a Google For Work account which I don't have and don't know how to get.
I'm at a loss for what I need to do to grant my account access to my own account.
Here is a paste of my auth code (with sensitive data removed of course): http://pastebin.com/RCdY8mX6