Sony has confirmed that they have heard the reports by some PlayStation 4 gamers who have not been able to log into the PlayStation Network on their PlayStation 4s.
Sony said that the issue was a widespread issue and they were working on it, this reported was ported via the official PlayStation Twitter account.
It looks like the recent login problems have been since the 1.60 firmware update so it might be something conflicting that may be a simple fix for Sony. This is only an assumption though, Sony has not yet officially identified the cause of the login problems on its next gen console.
Sony will keep people informed of the problem via their Twitter page, so if you are one of the few affected by it you should keep an eye out for any future updates, which will be quick.
Here is the tweet:
We are aware that some PS4 users are experiencing login issues. We’re currently looking into it and will provide an update soon.
— PlayStation (@PlayStation) February 5, 2014