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 ('698eb35ce412bee99f7973ce0ea24be1', -1, 1231545897, 1231545897, '26673f39', 10, 0, 0)

Line : 172
File : sessions.php