Windows 10, Outlook 365 icloud did not install properly. To repair it, you need to go to Apps and features, select icloud Outlook rom the app list and click MOdify:

Hey there cupgt3,

We'd like to learn more about what's happening, along with ruling out some general possible causes:

1. We understand that you uninstalled/reinstalled Outlook 365 on your Windows PC. What we don't understand is the reason you did regarding your Outlook account and iCloud for Windows. The more details you provide, the better we'll understand what's happening.
2. Sometimes unexpected behavior can be resolved with a restart. Has one been tried yet for your Windows PC?
3. Any updates available for iCloud for Windows, or even for Windows 10? If there are, please install them, then test for the same issue.

Cheers!