Office - Users encountering Error in Office 365 Apps

Issue:

Few users are getting a specific error while using Office 365 App. Few users have Windows and few having MacOS. 

Thank you for opening a ticket.  As per our conversation, we have a few users seeing the error - "There was a problem opening this rights protected message. Code: -2,147,168,444"

One is using Outlook for Mac and the other is seeing the error when using Outlook from the Portal via a browser.

Resolution:

Resolution: Followed below article​

https://gallery.technet.microsoft.com/Office-Message-Encryption-592d4872​