How to configure proxy in a C # application

I need to connect an application that I am developing in C # to the Internet through a proxy. For this I am using the class 'System.Net.WebProxy' of .NET in the following way:

var webProxy = new WebProxy("proxy.uh.cu/estudiantes.pac", 80);
webProxy.Credentials = new NetworkCredential("[email protected]", "myPassword");

and even then, the application does not connect. Am I doing something wrong here?