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 ('23288c9c64905a531a9c98db2ef0eab1', -1, 1539823039, 1539823039, '36a2766b', -2, 0, 0)

Line : 187
File : sessions.php