Nginx doesn't call the proxy_pass url, and gives a 404,

Question

I have a big problem with NGINX, it simply doesn't call the proxy_pass scripts anymore. this problem persists since we have changed the destination to another server (it was on the same switch before, now it's across the athlantic) I tried to output debug logs, but nginx logs the same...so no ideea what's happening what I know by checking the remote logs is that the script.php isn't called anymore if I do it manualy for the nginx server it calls it, so route's ok..

here's my config:

  location /check {
           proxy_pass http://mydomain/script.php;
           proxy_redirect     off;

           proxy_set_header   Host             $host;
           proxy_set_header   X-Real-IP        $remote_addr;
           proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;

           client_max_body_size       1000m;
           client_body_buffer_size    128k;

           proxy_connect_timeout      90;
           proxy_send_timeout         90;
           proxy_read_timeout         90;

           proxy_buffer_size          4k;
           proxy_buffers              4 32k;
           proxy_busy_buffers_size    64k;
           proxy_temp_file_write_size 64k;

       }