Not able to update the wcf service reference

I have an asp.net application which is using the WCF service. I am able to call the WCF method from my application and as well I am able to hit the breakpoint in the WCF service method. But I am getting an error while updating the service reference. I am getting the below error.

Error details

The URI prefix is not recognized. An error occurred creating the configuration section handler for system.serviceModel/bindings: The parameter is incorrect. (Exception from HRESULT: 0x80070057 (E_INVALIDARG)) (J:\MyProj\app.config line 4) The parameter is incorrect. (Exception from HRESULT: 0x80070057 (E_INVALIDARG)) If the service is defined in the current solution, try building the solution and adding the service reference again.

app.config

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <system.serviceModel>
        <bindings>
            <customBinding>
                <binding name="NetTcpRelayBinding_IWCFService">
                </binding>
            </customBinding>
            <netTcpBinding>
                <binding name="NetTcpBindingEndpoint">
                    <security mode="None" />
                </binding>
            </netTcpBinding>
        </bindings>
        <client>
            <endpoint address="net.tcp://localhost:8150/Services/WCFService" binding="netTcpBinding" bindingConfiguration="NetTcpBindingEndpoint" contract="WCFService.IWCFService" name="NetTcpBindingEndpoint" />
        </client>