Return a string from a restful ASP C#

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C#

web

API

Hello,
I am trying to return just a simple string after executed a store procedure using restful in c# .
This is my code (i know it is not a good code)
<pre> 
public string Get(string numero)
{
    string conexionString = "";
    SqlConnection conexion = null;
    var answer = "";
    try
    {
       conexion = new SqlConnection();
       conexion.ConnectionString = conexionString;
       conexion.Open();
       SqlCommand cmd = new SqlCommand("validar_cliente_factura", conexion);
       cmd.CommandType = CommandType.StoredProcedure;
       cmd.Parameters.Clear();
       cmd.Parameters.AddWithValue("@CTE_NUMERO", numero);
       SqlParameter returnValue = new SqlParameter("@RESPUESTA", 
 SqlDbType.NVarChar);
       returnValue.Direction = ParameterDirection.Output;
       cmd.Parameters.Add(returnValue);
       cmd.ExecuteNonQuery();
       answer = (string)returnValue.Value;
    }
    catch (Exception)
   { }
   finally
   {
      conexion.Close();                
   }
   return answer;
  }

When i run: https://localhost:44322/API/Test/A-5367
<message>No HTTP resource was found that matches the request URI 'https://localhost:44322/API/Test/A-5367'.
<messagedetail>No action was found on the controller 'Test' that matches the request.

What I have tried:

I had try some examples including the one when you created the example which is use

// GET api/values/5
      public string Get(int id)
      {
          return "value";
      }