Please could you confirm if you are still having this issue? I have visited the URL given above in Chrome and the player is rendering for me. Please do let me know if this still isn’t showing for you.

I accidentally fixed it by deleting an old WordPress plug-in that had been retired. It was called media-element. I didn’t realize that it had been retired.

When I deleted it, it must have allowed the regular one to work correctly.

Thanks for checking, I meant to come back here and close this as “self-solved by accident.”