I found out what the problem was, at least for me. The plugin added a widget on my main page, which is built with Elementor.
It added this code to my page: (In the Elementor editor appears as a grey bar with the characters </>, if you click it, you can see the code)
<!– Load Facebook SDK for JavaScript –>
<div id=”fb-root”></div>
<script>
window.fbAsyncInit = function() {
FB.init({
xfbml : true,
version : ‘v6.0’
});
};
(function(d, s, id) {
var js, fjs = d.getElementsByTagName(s)[0];
if (d.getElementById(id)) return;
js = d.createElement(s); js.id = id;
js.src = ‘https://connect.facebook.net/en_US/sdk/xfbml.customerchat.js’;
fjs.parentNode.insertBefore(js, fjs);
}(document, ‘script’, ‘facebook-jssdk’));</script>
<!– Your customer chat code –>
<div class=”fb-customerchat”
attribution=setup_tool
page_id=”109733547295517″
theme_color=”#3E78B2″>
</div>
If you are using Elementor, all you have to do is edit your page with Elementor, look for this widget and delete it. I don’t know if this happens with other builders too.