An error occurred while trying to download D2. There was a problem authenticating your download. Please go to http://www.blizzard.com/account/ to start a new download.
Note: Mac OS 10.15 Catalina and newer versions do not support 32 bit applications. You cannot install Diablo II on most recent Mac systems.
This error indicates a file permissions problem. Make sure you have administrator permissions, then download a new installer from our downloads page.