Twitter card share button

Question

I have issues with Twitter share button, I have this code as an input:

<meta name="twitter:card"        content="summary">
<meta name="twitter:site"        content="@citydesigning">
<meta name="twitter:title"       content="City Design">
<meta name="twitter:description" content="I recommend this epic City Design online course at https://stepic.org/city #stepiccity">
<meta name="twitter:creator"     content="citydesigning">
<meta name="twitter:image:src"   content="https://stepic.org/static/classic/city/images/sharepic.png">

and

<a class="twitter" 
   href="https://twitter.com/intent/tweet?url=https://stepic.org/city" 
   target="_blank"></a>

But it returns no results when sharing, only this text: "https://stepic.org/city" instead of all Twitter card information (like image and some text) when clicking "View summary" on Twitter's feed.

Can you help me, pleasee?

Answer 1

Domains need to be approved before Twitter Cards will work. Use Twitter's validator and then click "request approval":

https://cards-dev.twitter.com/validator