Access_denied when accessing the Gmail API with scope https://mail.google.com/

I am trying to read / write emails / folders inside Gmail inboxes using Gmail REST API. By adding the following Google Authentication Scopes, emails can be read from the Gmail REST API without any problem:

https://apps-apis.google.com/a/feeds/compliance/audit/ , https://www.googleapis.com/auth/admin.directory.user.readonly , https://www.googleapis.com /auth/gmail.readonly https://www.googleapis.com/auth/admin.directory.group.member.readonly , https://www.googleapis.com/auth/admin.directory.group.readonly

Note. The https://www.googleapis.com/auth/gmail.readonly setting correctly allows reading from mailboxes.

However, I also need to delete emails. So according to the documentation at https://developers.google.com/gmail/api/auth/scopes?hl=ja you just need to include https://mail.google.com/ instead of https: //www.googleapis .com / auth / gmail.readonly . When adding the following authentication scopes:

https://apps-apis.google.com/a/feeds/compliance/audit/ , https://www.googleapis.com/auth/admin.directory.user.readonly , https://mail.google.com / , https://www.googleapis.com/auth/admin.directory.group.member.readonly , https://www.googleapis.com/auth/admin.directory.group.readonly

... the displayed error looks like this:

    2015-07-27 10:27:59 i.c.s.a.cv [DEBUG] failed get labels for user
    com.google.api.client.auth.oauth2.TokenResponseException: 403 Forbidden
    {
       "error" : "access_denied",
       "error_description" : "Requested client not authorized."
    }

      

        
        
        
      

    

Surely this is wrong on Google's part? What am I missing? Incorrect documentation? What scope of authority do you need to add?

I am interacting with the Google API Java client library. See: https://developers.google.com/api-client-library/java/google-api-java-client/reference/1.20.0/overview-summary

The delete request looks like this:

public void deleteMessages(Queue<String> messages, GoogleUserAdapter user) throws Exception {

    Gmail gmail = getService(user);

    JsonBatchCallback<Void> voidCallBack = new JsonBatchCallback<Void>() {
        @Override
        public void onSuccess(Void t, HttpHeaders responseHeaders) throws IOException {
            logger.debug("delete success");

        }
        @Override
        public void onFailure(GoogleJsonError e, HttpHeaders responseHeaders) throws IOException {
            logger.debug("failed to delete message:"+e.getMessage());
        }
    };
    while (!messages.isEmpty()) {
        if (Thread.currentThread().isInterrupted()) 
            throw new InterruptedException();

        BatchRequest batch = gmail.batch();
        for (int i = 0; i < MAX_REQUESTS; i++) {
            if (messages.isEmpty() || Thread.currentThread().isInterrupted()) 
                break;
            gmail.users().messages().delete(user.getId(), messages.poll()).queue(batch, voidCallBack);
        }

        batch.execute();
    }
}

      

        
        
        
      

    

Credentials are created as follows:

   private GoogleCredential getCredentials(JsonFactory jsonFactory, HttpTransport httpTransport, String impersonateAccount) throws Exception {

    Preconditions.checkNotNull(Strings.emptyToNull(impersonateAccount), "Google impersonate account is null");
     Preconditions.checkNotNull(Strings.emptyToNull(connection.getServiceAccountId()), "Service Account Email address is null");
    Preconditions.checkNotNull(connection.getServiceAccountPrivateKey(), "Service Account Private Key is null");

    GoogleCredential credential = new GoogleCredential.Builder()
          .setTransport(httpTransport)
          .setJsonFactory(jsonFactory)
          .setServiceAccountId(connection.getServiceAccountId())
          .setServiceAccountScopes(
                    Arrays.asList(DirectoryScopes.ADMIN_DIRECTORY_USER_READONLY, GmailScopes.MAIL_GOOGLE_COM,
                            "https://apps-apis.google.com/a/feeds/compliance/audit/",
                            DirectoryScopes.ADMIN_DIRECTORY_GROUP_MEMBER_READONLY, 
                            DirectoryScopes.ADMIN_DIRECTORY_GROUP_READONLY))
          .setServiceAccountUser(impersonateAccount)
          .setServiceAccountPrivateKey(connection.getServiceAccountPrivateKey().getPrivateKey())
          .build();
    setHttpTimeout(credential);
    return credential;
}

      

        
        
        
      

    

The exact error that occurs when uninstalling:

   failed to delete message:Insufficient Permission

      

        
        
        
      

    

Jamie