Microsoft Outlook 2016 "Could not read the calendar. Unknown error"

iCloud version 5.1 Windows 10 latest build Outlook 2016 Dell XPS8300

iCloud installs fine and without error messages. iCloud Contacts and Reminders are OK but when I access iCloud Calendar I get this message: "Could not read the calendar. Unknown error"

Three installations on other similarly configured PCs were flawless with all features working perfectly.

Have reinstalled Office 365 and iCloud 5.1 on affected PC several times with same error occurring when accessing iCloud calendar.

Fixes and suggestions for troubleshooting are most appreciated.