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.

Click Win+R to open the Run dialogue box. Now type in Appdata, hit the Enter button, and then go to the Local Folder. Delete the Roblox folder and relaunch Roblox.