How is your MacBook Pro connected to the internet?
Unless it is connected directly to a modem, it's likely the MBP is connected to a router via ethernet or WiFi.
ISP <> modem <> router <> MBP
Depending on your hardware config, your modem+router might be combined in a single device (for instance if you are renting from your ISP) but the signal chain is still the same; modem first, then router.
The reason I mention all of this is that changing DNS on the MBP might not bypass the problem if the router is still using a problematic DNS server. You might need to login to your router and make the change there.
Did you note what DNS server your MBP showed in System Preferences > Network? It may have been pointing towards your router and letting your router determine which DNS server is actually in use. Sorry I'm a little fuzzy on the details about how Macs choose/behave when different DNS servers are configured in multiple settings.
Also, did you follow steps to flush the MBP DNS cache? Simply clicking Apply in System Preferences > Network won't actually flush the cache, it just tells the system to adopt your changes. So changing the DNS server on the MBP
might still be effective, but you won't know for sure if you don't flush the cache.
Also, some housekeeping questions to help avoid overlooking something else:
• You are using the BRD's auxiliary DC power supply and it is working correctly?
• You've tested a different known-to-be-good USB 3.x cable?
• You've tried connecting to a different USB port on the MBP
• You've tried by first shutting down (full shutdown not just restart), booting, then connecting the BRD?
• You've tried by shutting down, connecting the BRD, then booting?
• You've tried running Handbrake on a BR disc (make sure MakeMKV is not running)?
• You've created a new user account on the MBP, logged in and tried running only MakeMKV with the BRD connected?
• Do you use OnyX? Sometimes cleaning System/App/Internet caches, also rebuilding dyld shared cache, can "magically" rectify an otherwise elusive problem...
• Do you use EtreCheck? It might identify an issue that somehow relates to your problem
There are several threads here in the MakeMKV forums revolving around SDF/HK keys/DNS but at the moment it's hard to be 100% certain that's your problem.
Hang in there. Hopefully someone else will jump in here with troubleshooting ideas, too!