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 ('afc97fc1ce73351bb3a22c39a0a987e1', -1, 1539699002, 1539699002, '36e09618', 10, 0, 0)

Line : 187
File : sessions.php