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

Microsoft seems to have messed up again with its latest Windows 11 update, which borks the classic Outlook app. Earlier this ...

Microsoft has confirmed a known issue that prevents recipients from opening encrypted emails in classic Outlook.

Microsoft is looking into a newly identified issue in classic Outlook that prevents users from opening certain encrypted ...

A new Microsoft-issued software patch for Outlook (Classic) on Windows 11 inadvertently broke encrypted email support - ...

A new Outlook (Classic) update is preventing Windows users from opening encrypted emails. Microsoft confirms the bug and ...

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 ...