According to the official PlayStation Twitter account, PlayStation Network has suffered another outage. There is no news as to why, or whether it is down to another malicious attack, à la the Christmas DDoS attack on PSN by Lizard Squad.
We're aware that some users are experiencing issues signing into PSN – engineers are investigating. We'll keep you posted
— PlayStation (@PlayStation) February 2, 2015
As of this morning, PlayStation were reported to be slowly restoring the online gaming service:
Update: PSN services are in the process of being restored. Thanks for your patience!
— Ask PlayStation (@AskPlayStation) February 2, 2015