phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 2

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in) VALUES ('9dfdec260bb510a0c976544f8ce2eb86', -1, 1438628746, 1438628746, '365b90e8', -1, 0)

Line : 158
File : sessions.php