You also need another app to scan the QR code.Make sure you have the latest version of the Roblox app installed.If you see an option to log in with a QR code and you're having trouble, try these steps:
A success message will appear once your new device has logged in.Review all details before selecting Grant Full Account Access.After heeding the warnings, enter the one-time code shown on your new device, and click Enter.On your logged-in device, go to Account Settings then Quick Login.A one-time code will be displayed, which is only valid for 5 minutes.Click the Log In with Another Device button.On your new device, open the login page.To log in, you will need to follow the two sets of directions. When you use the quick log feature to another devices, make sure to remember: Our Quick Login feature allows you to log into a new device from another device that you’re already logged into, without requiring you to enter your password again.
