I'm sending an email to let's say `[email protected]` and Hotmail returns error email that the email was not delivered to `[email protected]` - same as when the account does not exist. So I have tried to register it and it says that I cannot register that account.

Why I cannot register it?

Is there any waiting period?

(Note that the account name that I'm trying to regiter is not something like `[email protected]` or `[email protected]`.)