Tawk.to Script adding to Invoice Ninja

Where should I add this script for my chat to work? I have tried a few places but it seems to break my login page. Any help is much appreciated.

<!–Start of Tawk.to Script–>
<Xscript type=“text/javascript”>
var Tawk_API=Tawk_API||{}, Tawk_LoadStart=new Date();
(function(){
var s1=document.createElement(“script”),s0=document.getElementsByTagName(“script”)[0];
s1.async=true;
s1.src=‘XXXXX’;
s1.charset=‘UTF-8’;
s1.setAttribute(‘crossorigin’,’*’);
s0.parentNode.insertBefore(s1,s0);
})();
<XscriptX>
<!–End of Tawk.to Script–>

You’d probably want to add the code in resources/views/public/header.blade.php