We've been getting calls from clients since about 10:30 this morning. Microsoft is having a major outage, and a lot of people can't log in to their email. It's hitting Microsoft 365 business mailboxes as well as free Outlook.com, Hotmail and MSN email accounts.
It's also affecting some people whose email isn't with Microsoft at all. If you use Gmail or Google Workspace in the new Outlook for Mac and your account is set up with "Microsoft sync technology," your email goes through Microsoft's servers, so Outlook can't get to it right now. Your email is still there at Google, and you can check it at gmail.com or in the Gmail app on your phone in the meantime.
This is on Microsoft's end. Removing your email account or reinstalling Outlook won't help, and it should start working again once Microsoft gets it fixed. Microsoft is posting updates on its status page. If your email still isn't working after that, contact us.
Want to chime in with your own complaints for Microsoft? You can add yours to this thread on Reddit. Our favorite comment so far:

Update
News coverage
There's been a lot of news coverage of the outage. Here are a few highlights.
- NBC News
Is Outlook down? Widespread outage hits Microsoft apps
Read article - 9to5Mac
Microsoft Outlook experiencing widespread outage
Read article - Windows Central
Microsoft 365, Outlook, Teams, OneDrive, and Copilot are ALL down right now
Read article - XDA Developers
Microsoft is suffering a major outage, taking down Microsoft 365, Outlook, Teams, OneDrive, and more
Read article - KPRC Click2Houston
Microsoft 365 outage disrupts Outlook email access, company says
Read article - The Apple Post
Microsoft confirms Outlook outage affecting thousands of users
Read article