Hackers take responsibility for crashing PlayStation and Microsoft’s Xbox networks over Christmas, asking for retweets in exchange for ending the problem. The group Lizard Squad took to Twitter to announce it was behind the connection failure, adding that it used distributed denial-of-service attacks to flood the networks with traffic and bring down the services. Lizard Squad said it would end the attack if users retweeted its statements. Xbox Live posted a message Thursday evening announcing it resolved the issue, but many PlayStation users continued to experience problems. Lizard Squad took credit for separate attacks on each network earlier this month.