jQuery animate not working on live server

I'm stuck. When clicking on a link in my menu, the menu should close and then there should be a smooth scrolling to the #-link.

My code is working fine on local but not on live-server.

I already checked if jQuery is loaded properly and there are also no errors in the console. Do you have any further ideas?

Here's my code:

$(document).on('click', "a[href^='#']", function(e) {
  e.preventDefault(); 
    
  $('html, body')
  .delay(300)
  .animate({
  scrollTop: $($.attr(this, "href")).offset().top
  }, 800);
});