Topic: Can't connect on Animal Crossing

So I was playing online on Animal Crossing but was suddenly disconnected out of nowhere. My buddy told me on tumblr that he accidentally shutdown his 3DS while we were playing. I told him is was okay but since that event I haven't been able to connect with anyone in Animal Crossing. Whenever I try to visit someone's town I get ERROR CODE: 018-0512, and whenever I try to invite people over they tell me they got an error code. I've searched it up and done everything Nintendo's Support site says and still nothing. I'm completely at a loss here now. Any one have any suggestions?

I got this error code when trying to play with a friend as well the only thing that got it working again was either putting my 3DS in DMZ mode on my router, or completely disabling my routers firewall.