Microsoft has announced that it is working on a fix for an issue that affects some Outlook in Microsoft 365 customers. The bug prevents them from accessing their email and calendars. The problematic version of Outlook was released on Current Channel on March 28, 2023.
Users may experience difficulty when attempting to add or access a group mailbox, add or access a group calendar, add, remove, or edit group members, or change something in the mail, such as marking messages as read, archiving, or moving them to other folders.
Microsoft has shared a workaround that can be used until the patch is released. Customers are advised to use Outlook Web Access (OWA) if they want to use the Groups feature, or return to Outlook Desktop version 16130.20332, which is not affected by the bug.