What region or country? Rental or puchase? Where rented or purchased?
Prior to the "Failed to Open Disc" message, was there any other info, perhaps starting with "DEBUG"? I've successfully backed up this disc years ago, no issues.
Odd, there's always some kind of info when a disc fails. Do you have debug logging enabled (View/Preferences/General/check "Log Debug Messages")? Open the .txt file created, highlight, and post here.
Debug log started at Sat May 20 15:21:41 2017 , written by MakeMKV v1.10.5 win(x64-release)
Using 524544KB for read cache.
001005:0000 MakeMKV v1.10.5 win(x64-release) started
001004:0000 Debug logging enabled, log will be saved as C:\Users\USERNAME/MakeMKV_log.txt
001003:0020 DEBUG: Code 233 at MnsStBaUqCr4jr6/epvrySTv:0
005010:0000 Failed to open disc
Application exited at Sat May 20 15:22:08 2017