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 ('edcc70b4fb268f1b9823317f41f5f3f5', -1, 1540132170, 1540132170, '36e05922', -4, 0, 0)

Line : 187
File : sessions.php