I'm not sure if this is my end or my friends' end. The first time I tried trading with my friend, it would connect to WiFi successfully. Then when I accept the invitation from my friend to trade, it would say its connecting, but then it shows me a blue screen and it says there's a connection error. There's no error number. And then it said it'll send me back to my last save point and that's it. We tried again for like 3 times before it actually worked. I'm not sure what made it work. Everything on my end seems fine. Then I just tried trading again today and it would still show the same message. I have no firewalls by the way.