Okay, this was happening to me about 5 minutes ago, but it seems to have improved slightly.
On opening the Mac App Store, it would tell me that it couldn't securely connect to the server and asks me if I want to go ahead anyway. Clicking 'Continue' just shows the blank grey background of the App Store. But once you click something like the 'Featured' tab, the display area would flash black and white as fast as possible.
Doesn't do this anymore, it just says an internet connection is required now.
On opening the Mac App Store, it would tell me that it couldn't securely connect to the server and asks me if I want to go ahead anyway. Clicking 'Continue' just shows the blank grey background of the App Store. But once you click something like the 'Featured' tab, the display area would flash black and white as fast as possible.
Doesn't do this anymore, it just says an internet connection is required now.