A user may report that when they insert a DVD into the MAC the DVD drive spins up and down a few times and then ejects the DVD. A specific example of this is a DVD with PDF's from a conference a faculty member went to.
We got this to work by changing a setting in System Preferences. Apple → System Preferences → CDs & DVDs → When you insert a video DVD. Set this to “Open DVD Player.” This setting was “Ignore.”
Of course, as most Macs no longer have optical drives, this article is quickly becoming obsolete…