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, session_admin) VALUES ('8703f14210dfd79410f3ce41444a3381', -1, 1416534835, 1416534835, '365274d2', 42, 0, 0)

Line : 187
File : sessions.php