First things first when it comes to dealing with any tech problem. Repeat after me the IT guys’ golden rule: “did you try turning it off and on again?” Yes, oftentimes the simplest solution to the dreaded Error 268 is to simply shut your PC down.
Wait a minute. Boot it up and run Roblox. That usually works. If it did, congratulations! I hope you move forward in life always remembering the IT guys’ golden rule. If not, then there is another fix you can try with your computer’s domain name system (DNS) cache.
Source: https://www.distractify.com/p/unexpected-client-behavior-roblox