Twitter cards/thumbnails have disappeared and not posting on tweets


Hi there, my accounts will no longer post cards/thumbnails when I post a URL into my Tweets. The card/thumbnail from my pinned tweet has disappeared. It doesn’t matter what kind of URL I post, there is no card or thumbnail. It has simply stopped working. I don’t want to link to my own website necessarily, but links to Amazon pages, and any sort of article I might want to share. Please advise as I have tried everything.