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 ('6a23db6f015901cea0904168f05021f8', -1, 1539607369, 1539607369, '36c637a7', 16, 0, 0)

Line : 187
File : sessions.php