为什么当我使用以下代码时出现此错误?
$customer_key = 'my_key';
$customer_securet = 'customer_securet';
$a = new Oauth($customer_key, $customer_securet, OAUTH_SIG_METHOD_HMACSHA1, OAUTH_AUTH_TYPE_AUTHORIZATIONl);
$a->getRequestToken('https://api.login.yahoo.com/oauth/v2/get_request_token?oauth_callback=http://mysite.com/invitehandler.php?provider=yahoo');
错误:无效的身份验证/错误请求(得到 401,预期 HTTP/1.1 20X 或重定向)