phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO elranchito_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('764f9a702780cd23c31ed5a3d02b1aac', -1, 1475311111, 1475311111, '365cc09c', 19, 0, 0)

Line : 172
File : sessions.php