Using classic Outlook for Windows in business environments
does not work
changed back to
imap-mail.outlook.com and is now working again
Win 10, Office 2021 Outlook (freestanding) > outlook.com and hotmail.com email accounts.
Interesting about server settings. In Jan 2024 when something similar occurred Microsoft allowed thousands of people to reconfigure email as if somehow all of these installations spontaneously messed up ... and then Microsoft acknowledged it was a back end issue and repaired the issue.
This time , for me started about a week ago with Outlook and Hotmail accounts. The existing accounts use the outlook.office365.com server as instructed by Microsoft, but attempts to configure new ones use imap.outlook.com or use exchange/ActiveSync settings at different attempts, and at different times the same credentials might be successful or fail.
Also, In both the previous instance from January and the instance which is occurring right now, "slamming" the server with many authentication requests sometimes forces the authentication to occur - eg 10 consecutive commands to send and receive all 7 email accounts results in some requests for passwords which then stop as the accounts finally log in. additionally as long as MS Outlook 2021 is running on the computer has not gone asleep on the network has remain connected there are no problems after having achieved proper authentication for all accounts
To your point, the imap.outlook.com server might be behaving better at the moment but also, on my PC after each time there is authentication of such a new account for then I am able to login again for a while with the long-standing accounts that use the outlook.office365.com server for that account. For that reason, in Outlook 2021 I have configured a separate Outlook profile where all accounts use the imap.outlook.com servers so the next time this occurs I can try that without manually re configuring accounts. I may also configure a 3rd profile with all accounts configured to exchange/ActiveSync.
None of this occurs with gmail accounts in same email applications, devices and network, nor does it occur in an android email app which properly handles modern authentication. The symptoms and behavior during both of these events seems to speak to the failure of back-end Microsoft services which allow IMAP accounts to connect with modern authentication specifically from Microsoft applications such as MS Office 2021.
Let's break that down: After a few years of forcing people to change server configurations for modern authentication and driving people to use Microsoft apps, Microsoft has created a situation where, from validly purchased MS software on validly purchased MS operating systems with properly configured accounts It is only the Microsoft products which fail.