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 ('1bb7c026917e79f5a9531f56dac0ace8', -1, 1414210406, 1414210406, '36a191fb', 8, 0, 0)

Line : 186
File : sessions.php