Microsoft finally added the long-promised support for the older IMAP protocol in its Outlook.com email service earlier this week, but the new feature apparently is still a bit buggy for some users, who have posted their issues in comments on the official Office blog.
Most of the user complaints have stated they cannot connect to Outlook.com with their IMAP-based email clients, such as Mac Mail and the Mac and Linux versions of Thunderbird. An example of this issue was reported on Saturday by Stan Wintraecken, who wrote, "Mac mail is only synchronizing my deleted messages map with outlook.com and not my inbox. It sends an error: Error 9. Server error. Please try again later."
In the same comment thread, Outlook.com Program Manager Ben Poon said Microsoft has "seen a handful of reports of users running into the error 9 so we"re looking into this with high priority." Some other people have also written that emails deleted in their IMAP client remain on the Outlook.com website.
Source: Microsoft | Image via Microsoft