When I reported this, I got a response back from a tech who shall remain nameless. I sent him the exact error along with other things it was doing on my devices and iTunes. He sent me back a generic response on how to reset my supposedly forgotten password. That got me a bit hot as I had check all the boards and this is widespread AND that he did not read the problem. So I sent a response back and I got a message saying that this is w widespread problem that they are working on.
I have no "real" problem with them having an issue. I have a problem with them not being truthful or taking ownership as with so many of you that have gotten solutions to clear their cache, etc.
I can't say that I know what the problem is, but in a similar environment that I've worked in, and seeing everything that people are reporting. It seems as if the problem lies in some sort of authentication server that verifies that you have a valid itunes account and password. (Just my speculation, nothing more).
I am glad that they are finally taking responsibility after numerous complaints. It just sad and frustrating when they send out generic solutions and make you go through the motions that they KNOW will not work.
Anyway, hope everyone gets their devices back up and operating soon.