We're currently experiencing a delay in the delivery of emails from Microsoft's free email services to addresses ending in @hotmail.com, @hotmail.be, @outlook.com, or @msn.com.
A support case has been opened with Microsoft to investigate and resolve the issue.
Update 11:00 AM: There's no update from Microsoft yet, but we're seeing more emails being delivered and that emails in the queue are gradually being delivered. However, it may take several hours for all emails in the queue to be processed.
Update 1:00 PM: All new emails are being delivered immediately to their recipients on Hotmail, MSN, and Outlook.com. We're also seeing the queue shrink. At the current rate, it could take several hours for all emails in the queue to be delivered.
Update 3:30 PM: We haven't received any feedback from Microsoft about a solution. The email queue is slowly shrinking, though.