More often than not its router incompatibility. Most default routers that service providers give you have stupidly strong firewalls and other P2P defences. It's really weird, and I've only ever seen it happen with nintendo things.
The router telstra gave me was the worst, and i had to go and by another one just to play some sweet sweet mario kart 7.
So far you're the only person i've come across that's had this problem with me since i got my new router. But you played Mossy and I played Mossy. So it doesn't make sense to me. But oh well.
GG's mossy. And corey, i can't join you. I keep getting 0515 error Also holy shit, i knew nesses back throw was good. I didn't know it was THAT good though. You died at like 80%, as Ike. ness's*