Error 400 in Roblox, Explained In a nutshell, Error 400 crops up due to a number of system-wide reasons, but they largely pertain to issues with the Roblox online servers.

When you’re trying to play Roblox and keep getting the “Bad Request 400” error, it can put a wrench in your plans.

Creating a game on Roblox, while far easier than making one from scratch, is not a cakewalk, given the number of possible errors users might encounter on their design platform.