Nginx 301 jumps, old "Feed" address can not access

Hi，Guys

I encountered a puzzling Feed error：

I try to set old.com 301 jump to new.com.

Then I found “old.com/?feed=rss2” not jump to the “new.com/feed/” this address. Access “old.com/?feed=rss2” it jumps to new.com Home here.

This is where the problem? How do I solve it? Thanks！

I am using Nginx+Varnish：

server {
listen 127.0.0.1:8080;
server_name old.com http://www.old.com;
return 301 http://www.new.com$request_uri;
}
server {
listen 127.0.0.1:8080;
server_name new.com http://www.new.com;
limit_conn one 20;
limit_rate 200k;
root /var/www/site;
index index.php index.html;
port_in_redirect off;
server_tokens off;

# Only allow these request methods
# Do not accept DELETE, SEARCH and other methods
if ($request_method !~ ^(GET|HEAD|POST)$ ) {
return 444;
}
# Deny certain Referers
if ( $http_referer ~* (babes|forsale|girl|jewelry|love|nudit|organic|poker|porn|sex|teen|nike|fat|golf|briefcase|education|webcam|zippo|hostgator|slaklyfreelay|outlook|seo) )
{
return 404;
return 403;
}