SAP WPB: Video does not play after publishing

Dear experts, the problem is that the video I add to the Book Page does not play on the portal after publishing.
In practice, it looks like this:

1. Using WPB Producer 9.5, I create a Book Page to which I add a video.

2. When for testing purposes I play this object in Producer 9.5, everything is okay, that is, the video is playing.

3. But after the publication of the Book, the Play button does not work on the portal, that is, the video does not play.

Question: what to do to make the video play on the portal the same as it plays on Producer 9.5?