phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO r2ok_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('13f4152e2a0f10412bfc99f764c21655', -1, 1524206710, 1524206710, '3650082c', 5, 0, 0)

Line : 187
File : sessions.php