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 ('bcb8e7a36474f327618a2da93e0c0258', -1, 1539677595, 1539677595, '36c6d41e', -2, 0, 0)

Line : 187
File : sessions.php