phpBB : Critical Error

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 ('5deb0223336841d7f588d8fc3efe493c', -1, 1467424672, 1467424672, '36a6d7b4', -1, 0, 0)

Line : 187
File : sessions.php