我正在尝试使用Google My Business Javascript API（https://developers.google.com/my-business/quickstarts/javascript）获取用户的位置列表 . 用户使用他的Google凭据成功登录，并生成oauth令牌 . 但是当我想要获得位置--->

var apiKey = 'xxxxxxxxxxxxxx';
        var clientId = 'xxxxxxxxxxxxxxxxxxxxxxxx';
        var gmb_api_version = 'https://mybusiness.googleapis.com/v4';

        let user = gapi.auth2.getAuthInstance().currentUser.get();
        let oauthToken = user.getAuthResponse().access_token;
        let xhr = new XMLHttpRequest();
        let req = gmb_api_version + '/' + 'accounts/' + user.getId() + '/locations';

        xhr.responseType = 'json';
        xhr.open('GET', req);
        xhr.setRequestHeader('Authorization', 'Bearer ' + oauthToken);
        xhr.send();

我在xhr.response对象中变为null .

javascript c# google-my-business-api