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 ('aaa2a7f3fd9504cb22e06bfc60f39d3b', -1, 1539872902, 1539872902, '36a6829d', 16, 0, 0)

Line : 187
File : sessions.php