Embedding a video in an email is not possible in any email provider or delivery platform.
That said, we are happy to offer a little trick that we here at Remarkety use which may help:
1. Drag a "Video" Content block to your email template
2. Add the video url to the "Video URL" box. You will notice that a preview image is automatically generated in the email template.
Here is an example of how this looks in an email sent to a Gmail account:
For more questions, contact firstname.lastname@example.org