If you're using Thrivecart and inserting LiveAgent button integration code as tracking codes, the tracking codes are enclosed in a <div> element with opacity set to 0, therefore they are invisible.
LiveAgent integration code places the button HTML code right next to the integration code, so the button is also invisible.
There is a simple solution to this problem, by using this slightly modified integration javascript code:
<script type="text/javascript">
(function(d, src, c) { var t=d.scripts[d.scripts.length - 1],s=d.createElement('script');s.id='la_x2s6df8d';s.async=true;s.src=src;
s.onload=s.onreadystatechange=function(){var rs=this.readyState;if(rs&&(rs!='complete')&&(rs!='loaded')){return;}c(this);};document.body.appendChild(s);})(document,
'https://testaccount.ladesk.com/scripts/track.js',
function(e){ LiveAgent.createButton('<your_button_ID>', e); });
</script>
This section of the default integration code
t.parentElement.insertBefore(s,t.nextSibling)
is replaced with the following:
document.body.appendChild(s)
The key change is that it doesn't place the HTML code of the button right next to the integration code, but places it at the end of HTML document just before <body> element, outside of the invisible <div> enclosing the tracking codes.