icloud error during authentication

Hello barbw427x,  

Welcome to the Apple Support Communities.  

This specific error could be related to security software installed to your Windows computer. Please go here for troubleshooting suggestions: Resolve issues between iCloud for Windows or iTunes and third-party security software.

It may also help to update your Windows computer and restart the computer if you have not done so recently.

Please note that some iCloud features require Windows 10 or later. You can find more details here: What is iCloud for Windows?

All the best!

This and connecting to iCloud via Windows browsers has been an issue for some time. See this link - iCloud encountered an error while trying … - Apple Community

There are a couple of fixes/workaround. One is to disable IPv6 for your network interface and the other is to turn off prioritization for the Killer network app. All the instructions are contained in the link.

Hope this helps!