Most transactions fails when using sumup-card payment widget SDK or REST API v0.2 in sumup

Question

I created checkout page using Payment Widget sdk like the following:

<div id="sumup-card">

<script src="https://gateway.sumup.com/gateway/ecom/card/v2/sdk.js"></script>
<script>
var sumupcard = SumUpCard.mount({
    checkoutId: checkoutId,
    showAmount: true,
    showFooter: true,
    locale: "de-DE",
    onResponse: function(type, body) {
        if (type=="success") {
            console.log(body);
        }
    },
});
</script>

When I click the submit button, the request is sent to https://api.sumup.com/v0.2/checkouts/:id

Most transactions fail. I wonder if v0.2 is the reason. So I tried to process checkouts via REST API v0.2 instead of v0.1, the result is same as sdk. But the transactions always succeed via v0.1. Who can let me know the url of sumup-card payment widget sdk file using v0.1 if it exist? Or let me know how to fix it? Please