Send gtag event from cross domain to parent domain

I'm trying to setup a send event from a iframe originated on my domain and placed on other domain (not mine). I placed the analytics code on the iframe.

<script async src="https://www.googletagmanager.com/gtag/js?id=UA-XXXXXXXX-XX"></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());

  gtag('config', 'UA-XXXXXXXX-XX',{ 'anonymize_ip': true });
</script>

Bellow that analytics code (with the UA-XXXXXXXX-XX from my parentdomain.com), I do a check to see if the iframe is not on my parentdomain.com and then, I set the tracker attribute to the div id ads_close:

<script>
ref = document.referrer;
whitelist = ["parentdomain.com"];
match = false;

for( var i = whitelist.length - 1; i >= 0; i-- ) {

 if( ref.indexOf( whitelist[ i ] ) > -1 ) { match = true; }

}
// If is not the parent domain, then add the onClick atributte to the ID "ads_close"
if( ! match ) {

  refer = document.referrer;
  var str1 ="gtag(\'event\', \'External\', {\'event_category\': \'yes\',\'event_label\': ";
  var str2 = "'";  
  var str3 = refer;
  var str4 = "'";
  var str5 = "});";
  var tracker = str1.concat(str2) + str3 + str4 + str5;
ads_close.setAttribute("onClick", tracker);

 }
</script>

The above code renders this way, IF NOT, on parentdomain.com:

<div class="adspop_close" id="adspop_close" onclick="gtag('event', 'Externos', {'event_category': 'yes','event_label': 'https://www.theotherdomain.com/post/'});"></div>

The problem:

Every time i click on the the div with the ID adspop_close, I cannot see the event on my parentdomain.com google analytics account...

The question:

What am'I doing wrong?

from Send gtag event from cross domain to parent domain