The PlayStation Network has been suffering intermittent issues over the weekend, and continuing into today. If you are having problems connecting to the PSN, you may have to just wait it out until access is restored.
Users will see 8071053D (PS3) and NP-2239-6 (PS Vita) errors when attempting to connect. It appears that only some gamers are affected, however. Sony have let to comment on the issue or indicate when it will be resolved.