Configuring preferences and options in Outlook.com
Well, I may have found a source for this myself:
"**Important:**Microsoft removed the ability to connect new accounts to Outlook.com on May 10, 2021. Accounts that were connected before May 10, 2021, will continue to sync as usual. To see your all your email accounts, calendars, and contacts in a combined inbox, download Outlook for iOS or Outlook for Android."
Apparently this very important facility was removed from Outlook 365 in 2018.
The simplest alternative is to use Forward from the connected account.
Why does the sync pane on Outlook.com say "try again later"?
What kind of misleading nonsense is that?
Why does the sync pane not say that this facility has been stopped?