Your code works fine for me, try clearing the browser’s cache and then try again. If the problem still persists, then try using incognito mode to try it again because this might be caused by extensions that have access to FCC that can cause the test to fail. Make sure there is not any extensions that can cause it to fail.
this error is not related to your code - we have been able to pinpoint it to a browser issue, please update your browser or try using a different fully updated browser