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 ('72a1be1cc30c24fddeb934d1299c50f0', -1, 1506357746, 1506357746, '3651585d', 2, 0, 0)

Line : 187
File : sessions.php