Content I uninstalled the New Outlook app and reinstalled it and that didn't fix anything. I am fairly sure it is something in my Microsoft account since all 4 of my Windows computers stopped working for the email at the same time. I have another Windows computer with a different Microsoft account and that is webpage working fine. ...

Content If both are signed in simultaneously, the system can confuse the authentication path. Log out of all accounts and sign in with only one — preferably the one with your Office 365 subscription. Fix issues with Windows, browsers, email, and other essential tools. Incorrect mail servers or ports will force Outlook to ask for credentials repeatedly. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. ...