phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO forum_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('b2210b98f0b3018ffcccd51ffbbc48aa', -1, 1539877635, 1539877635, '36e09618', 9, 0, 0)

Line : 187
File : sessions.php