Google Apps Script webapp server error -

I am new to Google Apps scripts, so I was trying to create the simplest script to work on. I want to deploy it as a web app so that it is not connected to any other Google app. I've deployed it as a web app:

However, when I go to it I receive an error: "We're sorry, a server error occurred. Please wait a little while and try again . " How do I fix it? Is my code or project missing something? It seems very small that my project only has the following Main.gs file:

  function doGet () {HtmlService.createHtmlOutput ('& lt; b & gt; Hello, World! & Lt; / B & gt; '); }  

Nothing appears in the log, and when I click Run or debug (with or without a breakpoint), I get a single error.

If my attempt is a wrong approach, what would the simplest script work?

Thank you.

I created a new app script, added that code, deployed it, and it was without error Run away from this file, and try again from the beginning It is not the code which is the problem when you learn new codes for the first time, things like that happen all the time, do not know what the problem is. You will need to take the documents at every step.