Profile: Support

Open plugin configure page and enable debugging.
Try to create the feed file and send me the plugin log file.
support@foxnetsoft.com

Add this new handler  in the web.config file

    <handlers>
      <add name="SitemapXml" path="sitemap*.xml" verb="*" type="System.Web.Routing.UrlRoutingModule" resourceType="Unspecified" preCondition="integratedMode" />

      <add name="AllhtmlFiles" path="*.html" verb="*" type="System.Web.Routing.UrlRoutingModule" resourceType="Unspecified" preCondition="integratedMode" />

Did you get this HTML code on HTML page at once or using Ajax?

Download the new release, I solved this issue.

No, plugin doesn't support multi themes JS files.
I advice you to add the new custom css style for this add to cart button for all themes and use it for only for JS selector.
Example

$('.ee-add-to-cart-button, .ee-product-box-add-to-cart-button')

>It is from plugin or Stripe admin ?
Yes, Stripe has special anti fraud filters (Radar). Create the rule for 3D Secure.

No, the plugin has only these preconfigured roles.

protected string GetCustomerRole()
        {
            if (_workContext.CurrentCustomer == null)
                return "Unknown";
            if (_workContext.IsAdmin)
                return "Admin";
            if (_workContext.CurrentVendor!=null)
                return "Vendor";
            if (_workContext.CurrentCustomer.IsSystemAccount)
                return "SystemAccount";
            if (_customerService.IsGuest(_workContext.CurrentCustomer))
                return "Guest";
            if (_customerService.IsRegistered(_workContext.CurrentCustomer))
                return "Registered";
            return "Unknown";
        }

Send me the error message from nop log or stdout log.

I did the new release. Download the new ZIP file and try it.
If you see the error message you need to open plugin configure page and enable debugging.  Try to login and send me plugin log file to email support@foxnetsoft.com