I have a similar issue at https://foljeton.dk/9068/merkel-med-maend
Running the validator I get
INFO: Page fetched successfully
WARN: No metatags found
I use the user-agent to serve another page than the one being shown in the browser.
You will see the meta tags are there, if you run
curl https://foljeton.dk/9068/merkel-med-maend -A Twitterbot
On https://foljeton.dk/9747/fra-bridget-jones-til-wonder-woman I get
INFO: Page fetched successfully
INFO: 13 metatags were found
WARN: Not whitelisted
So here some tags are found, but it’s still “Unable to render Card preview”
I have <meta name="twitter:card" content="summary_large_image"> and I’ve tried all the things listed in this thread and in Not Whitelisted, unable to render, or no image: READ THIS FIRST
I could really use some more elaborate debugging info.
Thanks