Configuring preferences and options in Outlook.com
Hi, I'm Diane and I'm happy to help you today.
The Connected Accounts feature was disabled July 1.
When Microsoft removed connected accounts from Outlook.com accounts not using the feature back in May 2021, they said anyone using connected accounts would keep them, but due to changes around the Microsoft cloud services, Microsoft disabled the Connected Accounts service for everyone on July 1. Microsoft did not do a good job sharing that it was going away - if you did not visit the Sync Mail page, you would not see the notification.
I noticed the banner below around April 1st.
This is my article on connected accounts: https://www.slipstick.com/outlookcom/outlook-com-connected-accounts/
If you prefer using the Outlook.com interface to read your mail, you can add the accounts to new Outlook. While its not quite the same as connected accounts (each mailbox will be separate), it has the same interface as Outlook on the web.
Forwarding mail to Outlook.com is also an option, although it’s not one I recommend now that more domains are using SPF and DMARC to identify potentially spoofed emails and drop them.
--Diane
Disclaimer: slipstick.com is a website I run as a Microsoft MVP, and the content is much more accurate and relevant than a general internet search. Although the website is in English, there are translation options under the search box.