Follow these tasks and let us know if these will work:
Check the Authenticator App: Make sure the app is installed and set up correctly on your device. Sometimes, the code might be there but not immediately visible.
Time Sync: Ensure that the time on your device is set correctly. Authenticator apps rely on the correct time to generate codes.
Update the App: Make sure you are using the latest version of the authenticator app. Older versions might have issues generating codes.
Switch Networks: If you’re using mobile data, try switching to Wi-Fi or vice versa. Sometimes network issues can prevent the app from generating codes.
Re-add the Account: Remove the Roblox account from your authenticator app and then add it again. This can sometimes resolve issues with code generation.
Contact Support: If none of these steps work, you might need to contact Roblox support for further assistance. They can help you troubleshoot the issue or provide an alternative way to verify your account.