phpBB : Fatale Fout

Error creating new session

DEBUG MODE

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

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('a4f17a6dfb6e61d51f7bbbb0b9e7dceb', -1, 1414831134, 1414831134, '36edeb0c', 3, 0, 0)

Line : 186
File : sessions.php