Validator not finding meta tags, but they're there

[seriesPnews]

I recently added twitter meta tags to my blog, I’m using the card, site, title, description and image tags. I also added a robots.txt file to allow any crawler to access any part of the site. I’ve curled the page with the twitterbot user agent and I can see the tags, but when I run a blog post through the validator it still says it can’t find the meta tags. Here’s an example post: http://www.seriesp.com/posts/13 and here’s the robots.txt file http://www.seriesp.com/robots.txt
Not sure what I’m doing wrong, everything seems to be correct.

[andypiper]

Interesting one here - it looks like your web server is sending back a blank Content-Type header, so our cards crawler is unable to determine that the response is HTML to be parsed. I’ve not actually seen this before, but I notice that you’re apparently serving your content from Amazon S3, so I don’t know if there’s a way to change this behaviour there.

[seriesPnews]

That makes perfect sense. I am able to set the content type when I upload objects to Amazon S3 and setting it to text/html fixed the problem, the validator now shows the card correctly. thanks so much!

[andypiper]