Videoscore: rendering issue on youtube

 Hello,
I usually put videoscores on Youtube but for 2 days I'm trying to put another (30 pages, voices and piano) but I don't get the usual result. When I send the score on Youtube I realize that the 30 pages are on a single page, so the result is tiny and unreadable. However, the sound works fine.
To try to understand, I put the voice score and the piano score separately on Youtube and there, it works!
But as soon as I put again the voice and piano score on Youtube, all the pages are on a single page.
I enclose the link so that you can see how it looks: https://www.youtube.com/watch?v=2JmvgLOGSXw
Any ideas about what is wrong with my score ?
Thank you very much