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 ('7d0ab23d40578fd1518ee5758ef17ee5', -1, 1513245076, 1513245076, '36a3d16d', 10, 0, 0)

Line : 192
File : sessions.php