title: Can we access GMAIL API using Service Account?
body: <p>I have a desktop application to read mail using GMAIL API over REST Interface. I want to use service account so that we can download the mails using domain setting and user interaction is null. I am successfully able to create Gmail Service instance but when I try to access any Gmail API method like fetching mail list or any other I get an exception saying </p>
  
  <blockquote>
    <p>Google.Apis.Auth.OAuth2.Responses.TokenResponseException:
    Error:"access_denied",    Description:"Requested client not
    authorized."</p>
  </blockquote>
  
  <p>I am done with all the setting at developer console and added scopes to my gapps domain.</p>
  
  <p>Does Gmail API support service account? Using the same setting  and service account I am able to get list of all files in Google drive using Drive service and API.</p>