C# code : Exchange says OK but doesn't send email

Dear Exchange community,

I need your help for the following issue :

I execute some C# code below for asking Exchange 2007 to send some emails, i get some positive answer from Exchange, BUT, i never receive the email.

Question : is there some missing configuration on my Exchange server, or some missing instruction in my C# code ?

C:\Program Files\Microsoft\Exchange Server\TransportRoles\Logs\MessageTracking :

2014-04-24T09:30:15.878Z,::1,SRV.mydomain.loc,::1,srv,,,STOREDRIVER,RECEIVE,3,<35A53654FA57D046B63B71C213CFD5239ECF79127E@SRV.mydomain.loc>,smith@mycompany.com,,3329,1,,,HelloWorld,test2@mydomain.loc,test2@mydomain.loc,04I:

Answer from Exchange :

<ResponseMessage ResponseClass="Success">

...

<Trace Tag="EwsRequestHttpHeaders" Tid="9" Time="2014-04-25 09:12:23Z">
POST /ews/exchange.asmx HTTP/1.1
Content-Type: text/xml; charset=utf-8
Accept: text/xml
User-Agent: ExchangeServicesClient/14.03.0032.000
Accept-Encoding: gzip,deflate<m:ResponseMessages><m:CreateItemResponseMessage ResponseClass="Success"><m:ResponseCode>NoError</m:ResponseCode><m:Items /></m:CreateItemResponseMessage></m:ResponseMessages>

C# code :

static void Main(string[] args)
{
           ServicePointManager.ServerCertificateValidationCallback = CertificateValidationCallBack;
   string log = "";
   exchange_service = new ExchangeService(ExchangeVersion.Exchange2007_SP1);
   exchange_service.TraceEnabled = true;
   exchange_service.TraceFlags = TraceFlags.All;
   exchange_service.Credentials = new WebCredentials(userName, userPassword, domain);
   exchange_service.Url = new Uri("https://" + exchangeServerAddr + "/ews/exchange.asmx");
   if (null != exchange_service.ServerInfo)
   {
       Console.WriteLine("Exchange server: " + exchange_service.ServerInfo.VersionString);
       EmailMessage email = new EmailMessage(service);
                  email.ToRecipients.Add("smith@company.com");
       email.Subject = "HelloWorld";
       email.From = from;
       email.Body = new MessageBody("This is the first email I've sent by using the EWS Managed API.");
       email.Send();
   }
   Console.Read();
}

Regards

Eric