So, here's my mystery. I called Apple Support and we went through a bunch of testing. Discovered I can sign into my apple ID using either of my two other accounts, including one we set up called "New Test" this afternoon. I get in, no problem. But when I try to sign into anything OTHER than support ie iTunes, or App Store, I get "There is an error signing into the Apple Server."
No parental controls are on. There doesn't seem to be any issue regarding "Li'l Snitch" that lets me know when there is incoming/outgoing connections as this is cross platform and cross users.
So, any idea? I can actually LOG ON to another user, while the one that doesn't work is still logged in, and download, see purchases, see apps, etc.
It's got to be something really simple we are not seeing.
Any suggestions?