Collaborate recordings are not permanently available for either viewing or downloading. If you wish to keep a recording from term to term (and class to class), you should download these files and utilize other video-sharing options to share videos with students. For example, use
Yuja Media Library.
Within the Collaborate Recordings view, mouse-over the three dots to the right of the video you wish to download.
Choose download.
This will open your downloads or documents file (Finder on Mac and Windows Explorer on PC). Save the file with a unique title and in a place you can later find. The file will save as mp4, which is compatible with most video sharing and viewing platforms.