Preview unavailable

Hi,
I use XOT 3.5, php 7.5.
when i click on preview, near the file upload for video, the result is "preview unavailble", in every page with video or audio.
But when I click on Play, near Publish, all is ok.
I need usa preview for sync point.
Could you help me?
Thanks

Hi
I don't think the preview option alongside the media upload works for anything but images at the moment. I guess you are asking because you have used that function in the old Flash editor or have seen a guide for creating sync points that refers to the old Flash editor?

For now the best way to work out the sync points you need is to play the video offline, or if Vimeo etc via their online player and make a note of the sync points required and then add/set the nested pages manually according to those timings.

HTH
Ron