This is a topic that really threw me for a loop – I have an application which displays a receipt, but it was unable to display it properly. The issue was that my application is running on Domain A (mia.web-performance.ch) and the store that created the receipt is running on Domain B (pia.web-performance.ch). Whenever you clicked the link to view the PDF, you got a blocked page instead.
I spent quite some time searching for answers online, but unfortunately, most of the results I found were unhelpful and didn’t provide any real solutions.