phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 2

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('778e08eacce9aa8aef92cd8c3d2239c5', -1, 1766668884, 1766668884, 'd849d83c', 2, 0, 0)

Line : 187
File : sessions.php