It's hard to explain but the web site you're using has no direct connection to the system which actually pays lightning invoices. Sending Hive is the only way that system knows to do something. As a result I can't really communicate back except via a transfer of Hive.

Lightning can fail in a zillion ways and I've tried to account for them all, every now and then it fails in a different way! Anyway as soon as I know about it, I can fix it.