Lightview: Video not available

Hello,

I use Lightview Plus Version 2.5.3.6
Until now, no problem. It was great.
Now, for the latest youtube video I try to embed, I get a error icon thumbnail “Video not available”.
See this page: https://www.jocosite.net/adrien/adrien-videos/

All the other youtube links work.
Why not these ones? youtube code: P6ILrPdUxhI, YZomRssnohw or ia5Ny0Ruhw4

I tried to upgrade to the latest version 3.1.2 (downloaded and installed the new 3.0 light plugin too)

Then these video thumbnails do show up, but I have 3 issues which are even worse:
1. the video pop-up windows is the same size as the thumbnail
2. I lose the navigation on the nextgen picture galleries
3. I liked the old white background and the new skins don’t seem to quite replace what I had (frankly that’s just a nice to have if the nav can work)

Can you help me?
What can I do to either fix my youtube problem with the old lightview plus plugin or get the new 3.1.2 template to work?

Thanks,
jordl