https://issues.apache.org/jira/browse/AMQNET-498

Reduce log level to debug as it is not an error condition.
diff --git a/src/main/csharp/Connection.cs b/src/main/csharp/Connection.cs
index 242a3cb..1d82d6f 100755
--- a/src/main/csharp/Connection.cs
+++ b/src/main/csharp/Connection.cs
@@ -1167,7 +1167,7 @@
                 }
             }
 
-            Tracer.ErrorFormat("Connection[{0}]: No such consumer active: {1}", this.ConnectionId, dispatch.ConsumerId);
+            Tracer.DebugFormat("Connection[{0}]: No such consumer active: {1}", this.ConnectionId, dispatch.ConsumerId);
         }
 
         protected void OnKeepAliveCommand(ITransport commandTransport, KeepAliveInfo info)