CredentialCache.DefaultNetworkCredentials is empty when using TransportWithMessageCredential

I am currently trying to use TransportWithMessageCredentials and https in my wcf project. I set both client and server security mode = "TransportWithMessageCredential" and clientCredentialType = "Windows".

When I go to get credentials from CredentialCache.DefaultNetworkCredentials, the username, password and domain are empty.

Any reason they would be empty? If they are always empty, where can I get the credentials?

How can I transfer the registered user credentials to the service without requesting them for login?

Client binding

<basicHttpBinding>
    <binding name="ClientHttpEndpoint" closeTimeout="00:01:00"
    openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:02:00"
    allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard"
    maxBufferSize="4194304" maxBufferPoolSize="524288" maxReceivedMessageSize="4194304"
    messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered"
    useDefaultWebProxy="true">
        <security mode="TransportWithMessageCredential">
            <transport clientCredentialType="Windows" proxyCredentialType="None" realm="" />
            <message clientCredentialType="UserName" algorithmSuite="Default" />
        </security>
    </binding>
</basicHttpBinding>

server binding

<basicHttpBinding>
    <binding name="WindowsTransportCredentialBinding" maxBufferSize="524288"maxReceivedMessageSize="524288">
        <readerQuotas maxDepth="128" maxStringContentLength="1048576" />
        <security mode="TransportWithMessageCredential">
            <transport clientCredentialType="Windows" />
        </security>
    </binding>
</basicHttpBinding>

...

<service name="Test.DiagnosticService">
    <endpoint binding="basicHttpBinding" bindingConfiguration="WindowsTransportCredentialBinding" name="ClientDiagnosticEndpoint" contract="Test.IDiagnostic" />
</service>

Code for setting username and password

ChannelFactory<IDiagnostic> test = new ChannelFactory<IDiagnostic>(DIAGNOSTIC_ENDPOINT_NAME);
test.Credentials.UserName.UserName = "TestUser";
test.Credentials.UserName.Password = "User";
return test.CreateChannel();