I cannot register a specific Hotmail account

Question

I'm sending an email to let's say xyz@hotmail.com and Hotmail returns error email that the email was not delivered to xyz@hotmail.com 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 resiter is not someting like mail@hotmail.com or admin@hotmail.com)

Answer 1

Hotmail will not let anyone else register with an existing Windows Live ID username before 365 days after that username has been cancelled/deleted.

It may also be possible that someone has registered a Windows Live ID username without opening a hotmail account. In that case, nobody else can use that Windows Live ID username in a hotmail email-address.