Thanks for your question.
You need to backup your credentials in authenticator, if ths was not done unfortunately you can only resolve this by contacting support or asking your admins/support to reset your account. So in this case if the app is roblox, get in contact with Roblox support.
You can reach the MS support team via the global support numbers here:
You can mark it 'Accept Answer' and 'Upvote' if this helped you
Regards,
Abiola