Sending, receiving, and organizing email in Outlook.com
Since even your usual spam has stopped, I would first sign in to Outlook on the web and check the Junk Email folder and Deleted Items, just in case the mail is arriving but being filtered out of the inbox. It is also worth checking that your mailbox is not full and that no sender is on your blocked senders list. If everything looks clear there, try sending yourself a test email from another account and sign out and back in, as that helps show whether new mail is reaching the account at all.