How to resolve 'Temporary problem completing your request' when deauthorizing computers for iTunes?

I'm trying to deauthorize computers and devices that I no long use or in some cases even have. And I keep getting the message that "There is a temporary problem completing your request. The iTunes Store is temporarily unavailable. Please try again later".

How much "later" do I have to wait?

[Re-Titled by Moderator]

Original Title: Deauthorizing computers for iTunes