paypal in-context checkout loading in lightbox and after few seconds revert to classic express check

paypal in-context checkout loading in lightbox and after few seconds revert to classic express check out. i read this post paypal in-context checkout reverts back to classic express checkoutbut it didnt help

<formclass="ajaxasync"><buttonid="t2"type="submit"class="checkout"class="paypal-button-hidden"><imgsrc="https://www.paypalobjects.com/fr_FR/i/btn/btn_xpressCheckout.gif"></button>


$scope.paypalArray['method']="SetExpressCheckout";
$scope.paypalArray['PAYMENTREQUEST_0_AMT']="1.00";
$scope.paypalArray['PAYMENTREQUEST_0_CURRENCYCODE']="USD";
$scope.paypalArray['PAYMENTREQUEST_0_PAYMENTACTION']="Sale";
$scope.paypalArray['returnUrl']="https://devtools-paypal.com/guide/expresscheckout/curl?success=true";
$scope.paypalArray['cancelUrl']="https://devtools-paypal.com/guide/expresscheckout/curl?cancel=true";
$scope.paypalArray['version']="124.0";
$scope.paypalArray['USER']="";
$scope.paypalArray['PWD']="9MKJCKB9JLSDEHD";
$scope.paypalArray['signature']="ABObRIVX-x21JGHTHGJJKLyToPvwtHhA90pM0a-gaGJs54hytrf2OzBfd";
$scope.paypalArray['L_PAYMENTREQUEST_0_NAME0']="item";
$scope.paypalArray['L_PAYMENTREQUEST_0_AMT0']="1.00";
$scope.paypalArray['L_PAYMENTREQUEST_0_QTY0']="1";


window.paypalCheckoutReady =function(){
paypal.checkout.setup("56EJUS986TVWQ",{
environment:'sandbox',
click:function(event){event.preventDefault();var url = paypal.checkout.urlPrefix +"EC%2d54U76817C6392042J";
paypal.checkout.startFlow(url);},
button:['t2']});};
the first api call i am doing to get token return with success. after i put the token to open the paypal lightbox window. the light box open for a few seconds with blank page and then redirect to classic display express checkout. I couldent find any solution for that. The wired part is that if i copy paste the example form paypal its works well : http://plnkr.co/edit/RifUli3hDIq6kQJI0Ujc?p=preview

thanks in advance.