title: YouTube video insert fails with 401 Unauthorized youtubeSignupRequired
body: <p>I'm uploading videos to many customers using Google API v3 with PHP client lib, it works for most of them so I guess the issue is not in my code.
  For the customers that fail, it always fails, so I believe the problem is with their authentication, however, for these customers I do get categories list with no problem, it's just the video upload that failed.
  That made me think it's because of the scopes I used during the authentication, but I used the same scopes for all my customers, those that work and those that don't.</p>
  
  <p>Any idea?</p>
  
  <p>Thanks,
  Tan-Tan</p>