If you still haven't got it working and have tried turning off the firewall, the following might be helpful to do.
1 check first that you are able to download other files from the net.
if so try the following, to do a totally clean re-install of Native Access.
2 download Revo Uninstaller free from
https://www.revouninstaller.com/revo-uninstaller-free-download/3 Run it and use its uninstall function to uninstall Native Access, then make sure that you don't close Revo uninstaller and do the advanced scan to remove any leftover files from the computer and registry, you will see the scan button in the Revo Uninstaller program.
I use Revo Uninstaller all the time, its a good program and just might solve the problem for you.