Since I upgraded my Macs (mini, Book Pro, Air) to El Cap, I cannot enter into the App Store: so, no Updates (except the system ones), no access to my Purchased programs. When I try, I'm asked for the password (for my Apple ID), both in App Store and iTunes, and the spinning gray circle starts rotating for ever. (The same happens to Messages, or iMessages, only T. Cook knows what is the right name for this - one of several unrealiable - Apple cloud services.) Now, the same Apple ID and password work without problems on my iPad and iPhone. I have reseted PRAM, tried other things found on the net, but with no avail. Since all that worked before, I suspect some El Cap bug. Any ideas?