Player card validation



I received the following message regarding my player card validation:

"The URL you provided for to use the player card did not validate. Please make sure the page contains valid metadata, then reapply for a Twitter card.

Thanks for your patience. See you soon!"

We have checked all the metadata and we seem to be fine - so we are at a loss as to why it is failing.

Would you be able to provide some additional detail?

Many thanks,