MailChimp Popup

So the solution is: 

1) Replace the script from the MailChimp with this one: 

<script type="text/javascript" src="//s3.amazonaws.com/downloads.mailchimp.com/js/signup-forms/popup/embed.js" data-dojo-config="usePlainJson: true, isDebug: false">
</script>


<script type="text/javascript">require(["mojo/signup-forms/Loader"], 
    
	function showMailingPopUp() {
	    require(["mojo/signup-forms/Loader"], function(L) { L.start({"baseUrl":"mc.us14.list-manage.com","uuid":"6934f1fe3fb030a931b1b20e5","lid":"492a096145"}) })
	    document.cookie = "MCEvilPopupClosed=; expires=Thu, 01 Jan 1970 00:00:00 UTC";
	};
	
	document.getElementById("getInvited").onclick = function() {showMailingPopUp()};
	document.getElementById("signUpBeta").onclick = function() {showMailingPopUp()};
</script>

2) Add identifiers to your buttons ("getInvited" and "signUpBeta")  
So they looks like this:

<a class="btn btn-default btn-lg" id="signUpBeta"> ... </a>

3) Should working :)