Dropdown does not work on Chrome

[Maximoy]

Hi, I own the website www.BAtourguide.com.ar
I am not an IT person but made my way with Bootstrap 2 years ago and put the website working online.
My site has many DROPDOWNS (i.e. the one that allows to change the language) which were working correctly until a few days ago.
Suddenly, they stopped working on CHROME (Desktop and mobile). I do not know exactly when. I checked the site today just by chance and noticed this issue. They DO work on Safari and Bing.
Any ideas?

If you need further information from my side to help solve the issue please do not hesitate to ask me.
I would appreciate any help to restore the functionality of my site.
Many thanks.

This is the code (you can see it online at https://batourguide.com.ar/)

<nav class="navbar fixed-top navbar-expand-lg navbar-dark" style="background-color: #1E6180;">
  <div class="container" role="navigation">
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>
     <a class="navbar-brand" href="index.html"><span style="font-weight: 700">BA</span> Tour Guide</a>
  <div class="collapse navbar-collapse" id="navbarSupportedContent">
    <ul class="navbar-nav ml-auto">
      <li class="nav-item">
        <a class="nav-link mr-4 text-white" href="index.html">TOURS</a>
      </li>
     <li class="nav-item">
        <a class="nav-link mr-4 text-white" href="en/tango-shows.html">TANGO SHOWS</a>
      </li>
     <li class="nav-item">
        <a class="nav-link mr-4 text-white" href="en/private-transfer.html">TRANSFERS</a>
      </li>
      <li class="nav-item">
        <a class="nav-link mr-4 text-white" href="en/about-us.html">ABOUT US</a>
      </li>
      <li class="nav-item">
        <a class="nav-link mr-4 text-white" href="en/testimonials.html">TESTIMONIALS</a>
      </li>
      <li class="nav-item">
        <a class="mr-4 text-white" href="en/contact.html"><button type="button" class="btn btn-outline-light">CONTACT</button></a>
      </li>
    </ul>   
  </div>
  
  <ul class="navbar-nav">
      <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle text-white" href="#" id="navbarDropdownlanguage" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false"><img alt="Language-English" src="images/flag_en.png" />   English
        </a>
        <div class="dropdown-menu" aria-labelledby="language">
          <a class="dropdown-item" href="pt/batourguide.html"><img alt="Language-Portuguese" src="images/flag_pt.png" />   Portuguese</a>
          <a class="dropdown-item" href="es/batourguide.html"><img alt="Language-Espanol" src="images/flag_es.png" />   Español</a>
        </div>
      </li>
    </ul>
  </div>
</nav>                  

[aribudin]

hello
your dropdown working fine in crome http://prntscr.com/w3sbe0