How to check with Twitter Card Validator
Go to https://cards-dev.twitter.com/validator and enter the target website URL.
After that, if there is an error message in the "Log" item, check the content of the error message and deal with the problem.
Error display example
In case of symptoms such as only images not being displayed
There is a high possibility of violating Twitter Card specifications.
Image formats that cannot be used with Twitter cards, images that are too large or too small, etc. will not be displayed.
Check out the detailed specs from the Twitter Developer Platform.