If you've tried all of these things and they didn't work, call Adobe (800-833-6687) or use their chat feature (you'll get a pop-up when the hyperlinked page loads). You can only use your Adobe ID on four devices (six registrations per device), so if you're using the ID on five or six devices (easy to do these days with smart phones, work PC/Mac, home PC/Mac, etc.), you'll might have to deactivate one or more of them. You can also ask Adobe to reset your Adobe ID, which means you'll have to re-register all your devices (easy), but it might solve your problem because it'll flush the server. This won't change your user name or password.