You may find that some embedded YouTube videos are showing "Video unavailable" when you try and view them in the app, like this:
The reason for this may be that they have copyrighted music in the background and for copyright reasons, YouTube automatically blocks these from playing if the EMBED setting is ON.
To fix this problem, on any videos that don’t play correctly please turn off the EMBED setting as follows:
1) Edit the article with the video in
2) click on the video preview image in the article
3) Click on the link manager button
4) Set EMBED to OFF, and save
5) Save the article
6) Refresh the info module by pulling down on the list screen (or homescreen) and then try playing your video again. You should see it play within the YouTube player.
To avoid this problem in future we'd recommend you either don't use music on your videos or if you have the rights to show the music by video, use Vimeo.