Error refreshing the OAuth2 token,message: ‘{ “error” :
“unauthorized_client”,“error_description” : “Unauthorized client or
scope in request.” }’

我在https://console.developers.google.com/project创建项目,创建服务帐户并下载.p12密钥.同时在项目设置中启用“Analytics API”,但它不起作用.这是我的代码：

$service_account_name = '<Service Email>@developer.gserviceaccount.com';
    $key_file_location = '<keyName>.p12';
    $key = file_get_contents($key_file_location);
    $cred = new Google_Auth_AssertionCredentials(
        $service_account_name,array(Google_Service_Analytics::ANALYTICS),$key,'notasecret','http://oauth.net/grant_type/jwt/1.0/bearer','<My email>'
    );
$client->getAuth()->setAssertionCredentials($cred);
$service = new Google_Service_Analytics($client);
$result = $service->data_ga->get("ga:<profileID>","yesterday","today","ga:pageviews");
print_r( $result);

我的项目有什么问题？请帮忙.