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 ('8d0bac0dc8d6f69684a07a85a16ddf19', -1, 1539661363, 1539661363, '36a174e1', 16, 0, 0)

Line : 187
File : sessions.php