location ^~ /sites/ {
    proxy_set_header X-Forwarded-Host $host:$server_port;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Server $host;
    proxy_pass http://web/index.php/apps/cms_pico/pico_proxy/;
}