This is very frustating. Get my example, handle many client account. I create a sandbox@*****.com.br and each client need to test. So, older Apple accounts have sandbox+(client)@****.com.br very handy to receive and test this email on Sandbox Apple Purchase. Now, i cant creat with plus ( + ) sign, or subaddress my email. What is happen to Apple? I need to create a billion accounts for handle all my clients??? Thats make no sense to prohibite that...