title: YouTube API v3 invalid grant after generating new refresh token
body: <p>We have an application which uses YouTube Data API v3 so we could be able to upload and manage videos on YouTube. For several days 
  we have not been able to upload videos in YouTube, nor to list corresponding playlists from the channel or to make any other actions which require making requests to YouTube Data API.</p>
  
  <p>When we try to list the playlists or to get a certain video by its Id or to upload a new video we get the following error message:</p>
  
  <blockquote>
    <p><strong>Error   {Error:"invalid_grant", Description:"Bad Request", Uri:""}  Google.Apis.Auth.OAuth2.Responses.TokenErrorResponse</strong></p>
  </blockquote>
  
  <p>We generated new refresh token from YouTube API but when we use it, we get the same error.
  Then we created a new application in YouTube developers page with new credentials and newly generated refresh token but we still are getting the same error.</p>
  
  <p>We think the reason the previous refresh token has become invalid is that the last time it was used is 7 months ago (the Google's documentation indicates that a refresh token expires if "The refresh token has not been used for six months.").</p>
  
  <p>Does somebody know why are not we able to use the newly generated refresh token and what should we do in order to make a successful request to the YouTube API?</p>
  
  <p>Thanks in advance!</p>