The upgrade coupons / tickets have been disabled and will be removed from the game. you can't use them or you get bugged. When you can get back on you should discard them
I am having the same problem... in my case i was upgrading an item i made and my game crashed....i cannot log into my character or create a new one..sorry if i seem new.. i am lol i was using a +12 upgrade ticket from popo's box