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 ('803cff85bb7ce3acc9897f9d6ad78226', -1, 1539788590, 1539788590, '36a285de', 16, 0, 0)

Line : 187
File : sessions.php