WCF restful service, server did not provide a meaningful reply - vb.net

Question

I am creating a restful service using WCF, I keep getting the error:
The server did not provide a meaningful reply; this might be caused by a contract mismatch, a premature session shutdown or an internal server error.
It is a time clock application, which takes in the username and the current time and stores it in a database for logging in/out.
I am new to the REST world can anyone help me?
My service interface:
ServiceContract(Namespace:="WCFRESTService")> _
Public Interface IService1
<OperationContract()> _
<WebInvoke(UriTemplate:="/login", Method:="PUT")> _
Function InsertUserDetails(ByVal username As String, ByVal time As DateTime) As String
End Interface
Service code:
<AspNetCompatibilityRequirements(RequirementsMode:=AspNetCompatibilityRequirementsMode.Required)> _
<ServiceBehavior(Namespace:="WCFRESTService")> _
Public Class Service1
Implements IService1
Private con As New SqlConnection("Data Source=TE-LAPTOP-001\SQL2008R2;Initial Catalog=timeClock;Integrated Security=True")
Public Function InsertUserDetails(ByVal username As String, ByVal time As DateTime) As String Implements IService1.InsertUserDetails
Dim strMessage As String = String.Empty
Dim errorMessage As String = String.Empty
Dim numcount As Integer = 0
numcount = getusercount(username)
If (numcount = 0) Then
Try
con.Open()
Dim cmd As New SqlCommand("spInsertLog", con)
cmd.CommandType = CommandType.StoredProcedure
cmd.Parameters.AddWithValue("#username", username)
cmd.Parameters.AddWithValue("#timein", time)
cmd.ExecuteNonQuery()
Catch ex As Exception
errorMessage = ex.ToString
Finally
con.Close()
End Try
strMessage = "You have Signed In at: " + time
ElseIf (numcount = 1) Then
strMessage = "Error: You need to SignOut before you can SignIn"
End If
Return errorMessage + strMessage
End Function
Public Function getusercount(ByVal username As String) As Integer
Dim count As Int32 = 0
Try
con.Open()
Dim cmd As New SqlCommand("spgetcount", con)
cmd.CommandType = CommandType.StoredProcedure
cmd.Parameters.AddWithValue("#username", username)
count = Convert.ToInt32(cmd.ExecuteScalar())
Catch ex As Exception
Finally
con.Close()
End Try
Return count
End Function
End Class
My client code
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim objervice As New ServiceReference1.Service1Client()
Dim result As String = objervice.InsertUserDetails("User1", DateTime.Now)
MsgBox(result)
End Sub
Service webconfig:
<system.serviceModel>
<serviceHostingEnvironment aspNetCompatibilityEnabled="true"/>
<services>
<service name="WcfRESTService1.Service1" behaviorConfiguration="WcfRESTService1.Service1Behavior">
<!-- Service Endpoints -->
<endpoint address="http://localhost:62131/Service1.svc" binding="webHttpBinding" contract="WcfRESTService1.IService1" behaviorConfiguration="web">
<!--
Upon deployment, the following identity element should be removed or replaced to reflect the
identity under which the deployed service runs. If removed, WCF will infer an appropriate identity
automatically.
-->
<identity>
<dns value="localhost"/>
</identity>
</endpoint>
<endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>
</service>
</services>
<behaviors>
<serviceBehaviors>
<behavior name="WcfRESTService1.Service1Behavior">
<!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment -->
<serviceMetadata httpGetEnabled="true"/>
<!-- To receive exception details in faults for debugging purposes, set the value below to true. Set to false before deployment to avoid disclosing exception information -->
<serviceDebug includeExceptionDetailInFaults="false"/>
</behavior>
</serviceBehaviors>
<endpointBehaviors>
<behavior name="web">
<webHttp/>
</behavior>
</endpointBehaviors>
</behaviors>
</system.serviceModel>
Client config:
<system.serviceModel>
<bindings>
<customBinding>
<binding name="WebHttpBinding_IService1">
<textMessageEncoding maxReadPoolSize="64" maxWritePoolSize="16"
messageVersion="Soap12" writeEncoding="utf-8">
<readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384"
maxBytesPerRead="4096" maxNameTableCharCount="16384" />
</textMessageEncoding>
<httpTransport/>
</binding>
</customBinding>
</bindings>
<client>
<endpoint address="http://localhost:62131/Service1.svc" binding="customBinding" bindingConfiguration="WebHttpBinding_IService1"
contract="ServiceReference1.IService1" name="WebHttpBinding_IService1" />
</client>
<behaviors>
<endpointBehaviors>
<behavior name="test">
<webHttp />
</behavior>
</endpointBehaviors>
</behaviors>
</system.serviceModel>

Answer 1

You don't need REST here (for such kind of client).
But if you want - try use stream for WebGet-responding from from REST method:
[OperationContract, WebGet(UriTemplate = "/SendMessage?login={login}&password={password}&phoneNum={phoneNum}&message={message}", BodyStyle = WebMessageBodyStyle.Bare, ResponseFormat = WebMessageFormat.Json)]
System.IO.Stream SendMessage(string login, string password, string phoneNum, string message, TimeSpan timeout);
//..
public Stream SendMessage(string login, string password, string phoneNum, string message, TimeSpan timeout)
{
//..
return new MemoryStream(Encoding.Default.GetBytes(jsonString));
}