DOMContentLoaded event is not firing code outside it working

index.html

<!DOCTYPE html>
<html>
  <head>
    <title>JavaScript  </title>

    <meta charset="UTF-8" />
  </head>

  <body>
    <div class="App"></div>

    <script src="./index.mjs" type="module"></script>
  </body>
</html>

index.mjs

console.log("Script loaded");   this is priting only

document.addEventListener("DOMContentLoaded", () => {
  console.log("DOM fully loaded and parsed");  //nothig prints inside this event
});

I want code inside DOMContentLoaded to work but its not working at all in simple code. Can someone tell me what I am doing wrong here.