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 ('7fce3a3956f168ab07ba7ab2941f5a22', -1, 1464083387, 1464083387, '36c62a5d', -4, 0, 0)

Line : 188
File : sessions.php