I’m having the same problem, but it doesn’t look like it’s been discussed in over a week. Any fix?
When my own tags didn’t work, I copied the example tags for the NY Times article and changed the tags one by one to see where the problem lies.
I can change everything but the image. It appears that twitter:image has to be a link to an image on the NY Times site, as it will work with any of their images, but if it’s a link to an image on any of the dozen other sites I’ve tried, I get the same error message stated above.