A customer adds an item and proceeds to the checkout page. Error 404 will be displayed when the customer attempts to finish the purchase (by pressing the Place order now), if the respective order-cycle closes while the customer is in the /checkout page.
Updated: In the case that the order cycle closes mid shopping the user will see an improved error message explaining what happened.
Redirection to the page /undefined - Snail 404
Manually navigating to the previous page will redirect the customer to the shopfront.
No workaround, but an edge case - s3
This is perhaps related to issue #5369 , since it also deals with the closing of an order-cycle on during the shopping-journey.
The agreed solution is that in the case that the order cycle closes mid shopping the user will see an improved error message explaining what happened.
Thanks for commenting this @lin-d-hop :heart: I'll update the "Expected behaviour" on this.
agreed with the above solution for papercut-ness
buttttttt just noting here how good it would be to have a countdown timer to when the order closes throughout the checkout process. Perhaps like when there's 1 hour till order cycle close theres a message that overlays on that shop.
Lots of online stores do this for sale periods and how long a system remembers items in a basket:


The sale usage of this UI is pretty icky and pushy sales but in this case I think it could be useful to have a timeout. But worth testing with shoppers to be sure.