Whenever you share a GIF through email, the Play and Pause button of Outlook desktop versions (2013 - 2019) gets added automatically to the thumbnail. This is not the expected behavior in other Outlook versions (office 365 and live) and this is applicable for Hippo Video, as well.
For instance, if you try to click on the play/pause button on the video thumbnail that is inserted from Hippo Video, it will only play/pause the GIF and not the video.
Except for the play/pause button on the video thumbnail, the rest of the thumbnail is a clickable hyperlink that redirects you to the video sharing page.
Is there a Workaround for the Issues with GIFs in Outlook?
Yes. the following workaround will resolve the issue,
Use a static thumbnail and ensure that your recipient can click on any part of the image to open the link to your sharing page.
Add text to nudge the user to click on the play icon in the bottom or add a link to video in the email body. Check out the below example.
Note: If your existing version of Outlook does not support GIFs, please check out this article for the solution.