Twitter card images no longer generating properly from WordPress site links

Question

I have been using the Yoast SEO plugin along with my WordPress site to allow Twitter to generate card preview images for tweets (which was working just fine). But recently, I used the SG Optimizer plugin to perform some optimizations on my site (enabling cache, compressing and minifying images, etc). But now, my feature images are not showing in the Twitter card validator when adding the URLs to my posts.

The strange thing is that I don't get any errors reported in the info box. For example, if I use this article URL as a reference:

https://www.midstory.org/after-industry-the-unusual-rebirth-of-mansfield-ohio/

When inputting the above URL into the Twitter card validator, I get a message saying "Unable to render Card preview" in the preview window. But the log output reports the following:

INFO:  Page fetched successfully
INFO:  30 metatags were found
INFO:  twitter:card = summary_large_image tag found
INFO:  Card loaded successfully

I'm not sure what to try next. I have tried the following troubleshooting steps and a few others according to this post here:

• image format being .jpg instead of .png
• Ensure robots.txt file is not blocking twitterbot
• Check SSL configuration
• Make sure page metatags contain proper content for twitterbot to grab image (checked with curl command in commandline and also in Google Developer console).
• Made sure link to feature image is correct

So far, none of the above has worked. Are there some other things I can check?

Answer 1

For anyone stumbling on this, it appears the preview feature of the card validator has been removed:

As of mid 2022, preview functionality was removed from the Card Validator. Previews did not match the final display in the Twitter clients and we recommend that you preview by pasting your URL into a Tweet composer in Twitter’s mobile apps or website. Cards do not get served via the API and may not render in third-party Twitter client apps.