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 ('c4b1a73ef3fc5e28c9e4dd8d74fbc0fb', -1, 1506203916, 1506203916, '36510849', 12, 0, 0)

Line : 187
File : sessions.php