We have MP4 files that are added to courses as a file resource. They show up in the Mobile app. as "Viewable on this app" and have a downward point arrow, however, clicking on the name does nothing, and clicking on the downward arrow, changes the arrow to a spinning icon for a few seconds, and then back to the downward arrow and nothing happens. (These MP4 resources were added from the desktop, not mobile and work fine from there.)