This is not a Cards issue and it is not related to the Twitter developer platform or API, so I’m not sure we can help you here.
As I mentioned, I successfully Tweeted a link to your site and the t.co shortening happened successfully (see https://twitter.com/evilpiper/status/669091926570901504). You could try putting that generated t.co link into your profile URL.
If you continue to encounter issues with twitter.com or the mobile apps, I recommend you use the support forms to raise a ticket. Thanks.