How old are your other DVD reading devices?
DVD RW is a fairly recent innovation and if you are trying to read the disks on a system that pre-dates this technology, that is a possible reason for your problem.
Samsung Galaxy S8 review
1995-2015: How technology has changed the world in 20 years
This poetic animation about monsters is illustrated in a Van Gogh painterly style
How to get WWDC 2017 tickets
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.