You must specify an email address, otherwise the program will not start.
On the main page of Roblox, click the gear on the right, then "Settings".
Go to settings.
Сlick "Add Parent's Email". Setting up Roblox, a window for entering an email address for user verification will appear.
You need to enter an email address and click on the "Add Email" button.
A letter from Roblox will be sent to your by email, where you will find the link "Verify Email", click on.