The Twitter Cards (summary_large_image) of my website are not always working. It’s not clear why they work at some urls and not work at the most of the urls. In de validator I get the error: ‘ERROR: Fetching the page failed because the fetcher cannot resolve the address.’
I followed all these steps. But nothing works :(.
Edit: after I posted this I see that there is some preview rendering here. So there is some metadata that is available I think.