I changed my Blogger template last night and re-added my Summary card markup to the template. Everything worked fine for a few minutes and then I noticed that test tweets were no longer showing my card. I went to the validator and it said that I’m not whitelisted for a summary card. I thought summary cards were automatically whitelisted?
http://www.the-newsroom.com is my website
This is the card code that has worked for me for ages:
<!-- twitter card details --> <meta content='summary' name='twitter:card'/> <meta content='@MikeJenkinson' name='twitter:site'/> <meta expr:content='data:blog.url' name='twitter:url'/> <meta expr:content='data:blog.pageName' name='twitter:title'/> <meta expr:content='data:blog.metaDescription' name='twitter:description'/> <meta expr:content='data:blog.postImageThumbnailUrl' name='twitter:image'/> <!-- end twitter card details -->