When a video is shared to Twitter it looks to Vidyard for information in order to understand how to format and display the video on its platform. This information obtained from metatags on the Vidyard sharing page.
Typically, the video is displayed in the format of a "card" with the thumbnail and link. When clicked, the video will play inline in the feed.
If Twitter encounters a problem reading the metatags on the Vidyard sharing page, the player will not appear inline as expected.
For example, the below image demonstrates what happens when the metatags from the sharing page do not properly unfurl to display the player thumbnail or description.
You may be using a custom CNAME for your Vidyard sharing page that Twitter does not recognize.
Use the Twitter card validator to confirm that the metatags on the sharing page are able to be read.
Ensure first that Enable search engine indexing has been set to ON for your sharing page. This will allow Twitter to properly read the metatags on the page.
If successful, Twitter card validator will present the video inline with a thumbnail, description (if applicable) and play button. It should also provide an option to whitelist your custom domain.
Click Request Approval to whitelist the domain.