If you click on the test button, after running the test you will see the full tests descriptions and eventually any error message.
In your case you are failing test #9
I can tweet the current quote by clicking on the #tweet-quote<a> element.
This <a> element should include the “twitter.com/intent/tweet” path in it’s href attribute to tweet the current quote.
#tweet-quote<a> element must have an href attribute : expected false to be truthy
Or in other words, it expect an a element with a href attribute pointing to the correct url.
Your element is missing the attribute entirely
I just pushed the twitter button at the Codepen page on my Safari browser on my IPhone, and it opened the Twitter page, but unfortunately the same thing which is 404 error happened to me as you said. I don’t really have no clue either.
But I think it might work fine, if you build this on your computer outside of Codepen.