My tweet card shows up with an error when I use the card validator tool.
Here is the error message:
INFO: Page fetched successfully
INFO: 14 metatags were found
INFO: twitter:card = promo_website tag found
ERROR: Required field missing (_forward_card_height_)
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Our tweet card url is https://cards.twitter.com/cards/18ce53x1mq8/a3r6
Included the img src width and height using the tags - twitter:image:width, and twitter:image:height: