Function of Pay with Amazon Plugin

-- HikaShop version -- : 4.2.2
-- Joomla version -- : 3.9.1
-- PHP version -- : 7.2.24
-- Browser(s) name and version -- : every

Hi Team,

we're trying to install the "Pay with Amazon" Plugin.
After install and setup with merchant id and the other requested keys, we_re checking the functionality with a testuser, defined in amazon seller central.
We've also installed the java origin and the return url is: shop.agentur-praxis-marketing.de/index.p...ayment=paywithamazon

What's the fact?
During checkout we've got the pop-up for login with amazon in sandbox mode (also the button on page), after the first login with the testuser the page returns to a blank page. In this stage you're no logged in in HikaShop and nothing happens. There's no further payment status, but the order is still generated without any customer- or delivery informations from amazon.

If you try to repeat these steps, it isn't possible, because the amazon login page doesn't appear again.

Is anybody here to help us with a hint, for finding the right solving?
Is there another amazon plugin available?

Every hint will be highly appreciate.

Hello,

We will need to reproduce your issue and your website to see it by ourselves for this, can you provide :
- A customer account references
- A backend/frontend access (with full access to your backend settings)

Use our Contact us form to provide these references, don't forget to add an Url link to this topic in your message in order to keep the link.
Awaiting news from you to move forward on your subject.

Regards