My friend and I can both join random games, or even host games and random people will join successfully. But we can't join each other no matter what we try. Our names will show up together in the game lobby, but then the "Failed to join game" error will come up.
This is on PS3, with no other connectivity issues between us. It's just Dead Space 3. We both tried setting up a DMZ on our routers, and then tried forwarding all the ports that were recommended elsewhere by EA. No luck.
I bought two copies of the game just so we could play online together. So far we've just spent 4 hours troubleshooting connectivity issues... it shouldn't be that complicated.
