Currency switcher simulation

Hello

Your link https://simulate.fcf-gajelabs.com/ is very useful but I am unable to test the checkout process with it.. For example when I try to add apples from the following listing: https://www.rhizomy.com/listing/apple-orchid/

and proceed to checkout, I get a blank screen..

https://snipboard.io/Bnqh9s.jpg

The page I need help with: [log in to see the link]