Scheduling and managing events using Outlook.com calendar
I'm using iCloud App version 7.13.0.14 and am having the exact same problem and have completed all of the steps to try to fix this issue all to no avail. This just happened after the latest windows update (09/11/19 timeframe). My PC advised me yesterday that I had updates pending a restart. After I restarted my PC all of the problems appeared, so IMO, it's connected some how..
Anyway, hopefully someone will get this fixed....