Displaying data from IR sensor into MIT App by using WiFi connection

MIT App Inventor Help
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9

I am seeing some holes in your Arduino code ...

Your Http code is:

void HTTP_handleRoot(void) 
{
  page = "<h1>Sensor to Node MCU Web Server</h1><h3>Data:</h3> <h4>"+String(data)+"</h4>";
  server.send ( 200, "text/html", page );
  delay(1);
}

but You did not see the response Sensor to Node MCU Web Server in a web browser?
That points to a setup problem in your Arduino code. (look for samples on this board.)

You send String(data) as your web response but you never modify the variable data from its boolean initialization value.

I advise getting decent web browser responses before trying to go further with AI2.