Buffalo refuses shipments

I've had a reasonable good experience importing stuff from Banggood in China via Buffalo. Lately however I often get the following message from Banggood when placing an order: "We regret to inform you that the item can't be shipped with the shipping method you chose due to some specific restrictions of the logistics carrier." No explanation is given why Buffalo won't ship the order, and I just have to cancel the order and ask for a refund. The stuff I order are just ordinary small electronic gadgets.