I decided to try running the LuLa App again. At the bottom of the bookshelf, indications of downloading began without any effort on my part. After 45 minutes, all 9 files downloaded. I started running the videos and watched for over an hour, everything worked well, no interruptions, clear video, no glitches, beautiful.
Somehow, yesterday, when I downloaded the app, it just stopped and there was nothing to indicate that it was incomplete.
Everything is working fine now, thank you.