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 ('051cea0e82c4a88553b3d0fba9cdb9f5', -1, 1505905901, 1505905901, '36c6368e', -4, 0, 0)

Line : 187
File : sessions.php