Beginner needs help with USB connection Windows 7

I am having trouble. I am using the terminal widget example from Blynk on a Mega2560… my app says device is offline and the Mega is sending serial monitor the auth code repeatedly… I’ve been trying to fix this for two days… what am I missing?

#define BLYNK_PRINT Serial1

#include <BlynkSimpleStream.h>

// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "9b98c51f79c0404e90cfd4a9ba8120e2";

// Attach virtual serial terminal to Virtual Pin V1
WidgetTerminal terminal(V1);

// You can send commands from Terminal to your hardware. Just use
// the same Virtual Pin as your Terminal Widget

  // if you type "Marco" into Terminal Widget - it will respond: "Polo:"
  if (String("Marco") == param.asStr()) {
    terminal.println("You said: 'Marco'") ;
    terminal.println("I said: 'Polo'") ;
  } else {

    // Send it back
    terminal.print("You said:");
    terminal.write(param.getBuffer(), param.getLength());

  // Ensure everything is sent

void setup()
  // Debug console

  // Blynk will work through Serial
  // Do not read or write this serial manually in your sketch
  Blynk.begin(Serial, auth);

  // This will print Blynk Software version to the Terminal Widget when
  // your hardware gets connected to Blynk Server
  terminal.println(F("Blynk v" BLYNK_VERSION ": Device started"));
  terminal.println(F("Type 'Marco' and get a reply, or type"));
  terminal.println(F("anything else and get it printed back."));

void loop()

Have you checked these directions and are leaving the command prompt window open?

Also, unless you have a TTL-USB adapter (on Serial1, pins 18 & 19 on the Mega), you cannot use both the USB link and the Serial Monitor at the same time… only one connection over a Serial port at a time.