My windows application has a timer which every few hours reads my outlook inbox...
In the code I am using:

On my machine where I run this app. if I have my outlook open then the following code works

ns.Logon(null, null, false, false);

But, if I have outlook closed, then on that line above I get the following error even if I use the credentials i.e. ns.Logon("domain\username", "pwd", false, false);

Could not complete the operation. One or more parameter values are not valid.

Eventually the idea is to have this app on the Prod. server so that it reads an email account which receives the required files to read...
How can I make the code to work without having outlook open?