Roblox error code 403 is caused by an authentication error. Here's how to fix Roblox error code 403 once and for all.

Now, find the Roblox folder in the opened directory and double-click on it to open it. After that, right-click on the blank space in the folder and select the New > Folder option.

Delete the Roblox folder from your AppData folder. Open a folder and access your C: drive. Go into Users > Your name. At the top, click View and make sure ‘Hidden Items’ is checked.

If Roblox is not downloading or installing on your Windows 11/10 PC, restart your PC and if that doesn't help, use the fixes discussed here.