PlayStation Network is currently suffering from connectivity issues today due to the large number of users attempting to take advantage of the network's on-going Black Friday sales. Games like Black Ops 3 and Assassin's Creed Syndicate are heavily discounted today for the PS4.
Sony states that they are fully aware of the issues and are working to address them. Among the services currently facing connectivity issues are PlayStation Store and account access, though players shouldn't have any difficulty playing multiplayer games online or downloading anything they purchase.
The network is expected to stabilize later in the day, but we'll keep you updated in case anything changes. In the meantime, hitting refresh while attempting to access the page should work, if it's stalled.
We are aware that some users are having connectivity issues with PSN this morning. Thanks for your patience as we investigate.
— Ask PlayStation (@AskPlayStation) November 27, 2015