iframe未加载到puppeteer中

Question

我的代码：

async () => {
   const browser = await puppeteer.launch();
   const page = await browser.newPage();

   await page.goto('https://example.com' , {
      waitUntil: 'networkidle2'
   }); 

   await page.screenshot({path: 'home.png', fullPage: true});
   let frames = await page.frames();
   await page.screenshot({path: 'home.png', fullPage: true});
   var iFrame = frames.find(f => f.url().indexOf("https://accounts.") > -1);
   const usernameInput = await iFrame.waitForSelector("[name=username]" , {visible : true});
   await usernameInput.type(email);
   const passwordInput = await iFrame.waitForSelector("[name=password]" , {visible : true});
   await passwordInput.type(password);
   const navigationPromisePortal = page.waitForNavigation();
   await iFrame.click(".primary");
   await navigationPromisePortal;
   var cookies = await page.cookies();
   await browser.close();

   return cookies;
}

我正在尝试从example.com获取cookie。但是每次帐户iFrame都不会加载。该页面由react构建。我该如何解决这个问题？