Hey there. The BUFFALO error occurs when there is a connection issue with Battle.net's servers. You may want to review our BUFFALO help article for more information about this issue. If that doesn't help: [quote][b]1.[/b] You may also want to try opening the battle.net launcher "Settings" and change the "When I open a game" option to "close the battle.net launcher completely" option. [b]2.[/b] Some players have suggested disabling Internet Protocol Version 6 (TCP/IPv6) on the PC might help with this issue. [b]3.[/b] You may want to change your region/server to another location. [b]4.[/b] Some players have suggested disabling the "Always require authenticator for login" option in your Blizzard account settings. [b]5.[/b] Some players have reported that disabling IPV6 has helped them with this issue. [b]6.[/b] Some players have reported that logging into their Battle.net account and Destiny 2 on another PC then logging out and logging into them on their first PC have resolved this issue. [/quote]