If you are receiving "Failed - Network Error" when trying to download a file from a website that uses Sucuri Firewall and the same error happens in more than one computer/network, please disable or ask your hosting provider or web developer to disable zlib.output_compression in your PHP configuration.

Usually you can disable it by adding this line in your .htaccess file:

php_flag zlib.output_compression off

Or adding this line to your php.ini file:

zlib.output_compression = Off

If it still doesn't work, please try disabling mod_defalte (Apache), gzip directive (NGINX) OR open a General Support Request.