Recently after a fresh install of Windows 10, I tired to reinstall iTunes.

While trying to authorize my computer for my iPhone Apps I got the following error:

“There was an error connecting to the Apple ID server”

Several reboots later, still no joy. I also noticed that I couldn’t connect to the iTunes store.

I found the following helps?

1. Right click on the Windows Start Menu Icon and select ‘Command Prompt (Admin)’
2. Type the following into the command prompt box followed by enter:
   netsh winsock reset
3. Reboot the computer

How this works: I’m not overly sure why it effects iTunes, but it’s similar to clearing the cache in your browser, just at a network level.

Hopefully this helps someone else.

Reference: https://discussions.apple.com/thread/7192420?start=0&tstart=0