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One alternative is to subscribe to iCloud calendar with your Exchange/O365 email accounts or any Outlook account, and then sync the same accounts in Outlook for Mac. See details:
An error occurred while saving the commentMargie Zelenske commented
I had case number 1408607553, and my issue was with the my outlook 2016 version 15.41 was not allowing me to view the read receipt option; I have yahoo, and the exchange option is not available for my type of account; IMAP is all I can have. With my Microsoft computer I had these option, and I had the same Outlook 2016; Mac is very expensive, but very Limited when it comes to Microsoft.