Hi, I'm Bernard. I'm happy to help!
Based on the Outlook.com Health Status, there was a recent issue affecting sign-ins, but mitigation steps have already been applied, and the service is being closely monitored.
This is a known issue, and updates will be provided through the link below.
https://portal.office.com/servicestatus
Under Microsoft consumer products > Show products > click Show Details under Outlook.com
If the issue persists, I recommend waiting for Outlook.com to be fully operational again.
Additional note: This is a public forum. I may respond shortly, but I apologize in advance for any delays. I am simply a fellow user trying to provide helpful insights and information.