"This video isn't available" when external user views shared video

Symptoms

In SharePoint, you share a video to an external or Azure Business to Business user. When the user tries to access the video, they see the following error message: 

This video isn't available.

There's something wrong with the video ID for this page.

Cause

This error occurs because the video at its current location can't get shared with external users. This includes Azure Business to Business users.

Solution/Workaround

To work around this issue, store the video in another location. For example, add the video to a SharePoint Online or OneDrive location that enables external sharing, and then share the video with the external users.