Ridiculous iTunes Cannot Connect to Store Unknown Error 11556
I finally found out on discussions.apple.com that somehow the Parental Control for blocking access to the iTunes store had somehow been activated, and that was why it couldn’t connect.
Why on Earth Apple doesn’t suggest this in the error dialog is beyond me. IMHO it’s very sloppy.
By the way, Firefox’s spell checker suggested “tribunes”, “tuneless” and “tuneups” for iTunes.