S3 through Nginx Proxy doesn't allow more than 10 files to be downloaded simultaneously

I setup a Nginx Proxy in front of my S3 object storage and I'm able to download files without any issues so far.

However, if I try to download the same file from, let's say, 30 different servers, at the same time, only the first 10-11 servers are able to continue downloading while the rest gets cancelled with the following error;

gzip: stdin: unexpected end of file
tar: Unexpected EOF in archive
tar: Unexpected EOF in archive
tar: Error is not recoverable: exiting now

This is the command I'm running to download the file;

sudo curl -f -Ls https://cdn.mydomain.com/files/somefile.tar.gz | tar xvz

And this is my nginx config file under /etc/nginx/sites-enabled/cdn.conf;

server {
    listen 80;
    server_name cdn.mydomain.com;

    if ($host != "cdn.mydomain.com") {
        return 444;
    }

    access_log /var/log/nginx/reverse-access.log;
    error_log /var/log/nginx/reverse-error.log;

    location /files {
        proxy_pass https://myBucket.s3.nl-ams.scw.cloud/files;
        proxy_set_header X-Real-IP $remote_addr;
    }
}

My nginx.conf is the default file that gets generated as I first installed the nginx on my server.

I don't know what's limiting this but how can I allow more concurrent downloads in this setup?