A bug in the new Outlook Calendar prevented users from adding calendar items when working with IMAP/POP3 accounts. Microsoft does not yet offer a real solution.
Microsoft has identified a problem in the new Outlook where users are sometimes no longer able to add new appointments to their calendar. Users have raised the alarm via Microsoft’s forums.
Only third-party email addresses affected
A specialist identified the issue and provided a workaround: The issue only occurs when a third-party IMAP/POP email account is set as the primary Outlook account. Anyone who can adjust this can avoid the problem. These are, for example, email addresses from Google. Addresses with a Microsoft domain do not have this problem.
By setting a Microsoft account as your primary email address, it is possible to re-create calendar entries in the current account. Microsoft Outlook has been struggling with bugs and problems lately. For example, the application crashed when users tried to copy text, and users with more than five hundred folders were no longer able to send emails.
There is no final solution to this problem yet, but the issue is on the agenda. The support forum topic remains open for users to provide feedback.