First you have to wait some time because the packing list is created in the background. You can see the icon of a clock on the right which means, that there are still activities pending. You have to reload the page, to see when the icon disappears. If the icon stays for more then 5 minutes or it disappears but you still get the message "No related packing list", then the start and stop date of the Trade Condiotion is probably not set correctly. It the start date has to be set before the dates set in the order and the stop date after. So to solve this issue, first correct the start and stop date in the Trade Condition and then clone the order. For the cloned order, the packing list will be created autimatically.