There is no fix available, but you can always revert to an older version.

PCWorld reports that Microsoft has confirmed a bug in classic Outlook version 2511 preventing users from opening encrypted emails. This issue significantly impacts business users and organizations ...

Forbes contributors publish independent expert analyses and insights. Davey Winder is a veteran cybersecurity writer, hacker and analyst. As regular readers of the cybersecurity section here at Forbes ...

Microsoft has shared a temporary fix for a known issue preventing Microsoft 365 customers from replying to encrypted emails using the Outlook Desktop client. This confirms customer reports regarding ...