Oracle Error: ORA-12541: TNS:no listener when I open connection

See more:

ASP.NET

Visual-Studio

Oracle

, +

Hi there,

I have a webapp, VS2013, C# and ASP.NET, and I use Oracle 12c as DB, so when I try to connect to DB from my webapp I got this error: ORA-12541: TNS:no listener, this is my code:

public bool OpenConnection(Label lbl)
       {
           try
           {
               using (cn = new OracleConnection(WebConfigurationManager.ConnectionStrings["RegistroConnection"].ToString()))
               {
                   if (cn.State == ConnectionState.Closed)
                   {
                       cn.Open();
                   }
               }
               return true;
           }
           catch (NullReferenceException nullExcept)
           {
               lbl.Text =  "Caught error: ." + nullExcept.ToString();
               return false;
           }
           catch (OracleException dbEx)
           {
               lbl.Text = "OraException - " + dbEx.Message;
               return false;
           }
           catch (Exception ex)
           {
               Exception current;
               current = ex;

               while (current != null)
               {
                   current = current.InnerException;
               }

               lbl.Text = "Db base exception - " + ex.GetBaseException().ToString();
               return false;
           }
       }

I have the connectionstring on my webconfig:

<connectionStrings>
    <add name="RegistroConnection"
    connectionString="Data Source=(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST =myServer)(PORT = 1521))(CONNECT_DATA =(SERVER = DEDICATED)(SID = sidname)));User Id=user;Password=password;"
    providerName="Oracle.DataAccess.Client"/>
  </connectionStrings>

the dll already added is:
- Oracle.DataAccess.Client

If i try to connect through Sql Developer I have a successful connection but on my webapp I have this error: ORA-12541: TNS:no listener

Please, somebody help me

I'll waiting for your response!

Thanks and Regards.