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 ('24d686f99e4203909b5852955c6da9d6', -1, 1540088692, 1540088692, '3650bc57', -11, 0, 0)

Line : 187
File : sessions.php