We're using a CommentThreads: list YouTube API Method to get all comments associated with a YouTube Channel, and for at least half a year it was working fine with YouTube v3 Data API www.googleapis.com/auth/youtube.readonly scope. The scope is read-only, as we only need to get comments, not write anything. Since a few weeks ago it's not possible to do that with a read-only scope (it returns 403 "Insufficient Permission" error), a full scope www.googleapis.com/auth/youtube.force-ssl is needed to list comments.
The token is obtained via Google OAuth2 process.
The read-only scope is an official scope for the API, and I couldn't locate any limitations on using it in the docs for list methods, and there seems to be no announced changes to the API (as it stopped working only recently). Did anyone else experience similar problems?
https://www.googleapis.com/auth/youtube.force-ssl
. So it seems that this method required this scope to work. – KENdi