Sending, receiving, and organizing email in Outlook.com
Hi. I'm Brian and I'll try to help.
Are you logging into the mailbox with a web browser at https://outlook.live.com/? If not, how are you trying to access the mailbox? Can you send messages? Do you see messages in the mailbox? Have you checked your storage at https://account.microsoft.com/? When you sent a test message, from another mail service I presume, did you receive any non-delivery reports? The non-delivery report should tell you why the message did not reach the recipient address.