WebService DotNet - A connection attempt failed because the

Hi guys

I create a project for consuming a webservice in Dot Net.
If I run on the Visual Studio everything runs ok, but if I try to run from Dynamics NAV the following error message appears:

A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. <IP address:80>

Steps that I follow on Dynamics NAV:
Copy the DLL file to the folder Add-Ins
Create a simple Codeunit with Global Variable (Type DotNet) to my DLL file.
On the code Instantiate the object and run the method.

Thanks for your answers.