Why I need A .net to install Express Vpn?

I can not install the VPN, because that I need a .net for my software, but why it needs that?

ExpressVPN app installation is very simple,the thing is that you need to have an 9-digit activation code. No problem if you can’t find the Dot NET framework along with the OpenVPN

Because it’s programmed in .Net Framework! just download and install “.Net Redistributable”