WCF引用失败有关问题

WCF引用失败问题，求助
我点发现按钮，找到的服务路径为http://localhost:1559/DGService.svc
但是
出错了

我想起DGService.svc文件是在sample.Web项目下的
于是我修改路径为http://localhost:1559/sample.Web/DGService.svc
但是
究竟怎么回事？

我的web配置如下：

<system.serviceModel>
        <behaviors>
          <!--添加WCF通讯类型-->
          <endpointBehaviors address="" binding="basicHttpBinding" contract="IServices">
            <identity>
              <dns value="localhost"></dns>
            </identity>
          </endpointBehaviors>
          <endpointBehaviors address="mex" binding="mexHttpBinding" contract="IMetadataExchange"></endpointBehaviors>
            <serviceBehaviors>
             
                <behavior name="">
                    <serviceMetadata httpGetEnabled="true" />
                    <serviceDebug includeExceptionDetailInFaults="false" />
                </behavior>
              
            </serviceBehaviors>
        </behaviors>
        <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
    </system.serviceModel>