Apple iCloud error #0x80004002 on Windows 10 1903 when syncing Calendar events

I also had this problem long term. I worked with both Apple & Microsoft level 2 help desk people and finally got it fixed. Here's what can cause this problem that no one would think of. It turns out that if you are using Outlook the program requires a default profile to be set up in Outlook itself and then you need to close Outlook and then run the iCloud setup for Outlook to get it to connect and not get the error message. If the default is not setup from within the File>Account Settings>Manage Profiles area of the program then the iCloud CP will throw this error. There is an additional wrinkle that needs to be worked with in a special way if there are multiple profiles that need to be switched between also. The iCloud CP does not like if you use the Outlook option to be prompted at startup for a profile. To switch between profiles you must go to the File>Accounts Settings>Switch Profiles and then close Outlook and restart it and at that point you will be prompted to select a profile to use. So, in short the convenient "Prompt For Profile At Startup" is not usable, it IS the problem.

Hope this finite explanation helps someone.