An elderly relation has a newish laptop (operating system is Windows 10) which like many newer laptops doesn't have a DVD drive. He bought an external DVD drive for backing up documents etc, which it manages to do. However, if he wants to play a DVD on the laptop via the external DVD drive he finds that he can't do this, although it can play CDs.

The DVD player software he is using is "VLC media player", which is able to play DVDs on this computer running Windows 10, although this pc was upgraded from Windows 7.

Any suggestions on how to fix this problem, please?