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 ('504ff0ed76d8b37bf2fe6c871d368146', -1, 1506358261, 1506358261, '3651585d', 3, 0, 0)

Line : 187
File : sessions.php