We believe we have resolved this. Let us know if you are still having an inability to connect to games. Player support is the best avenue as we can track large ticket numbers.
What happened? As a part of upgrading our NA game server fleet we encountered some networking issues this morning (/23 blackholing some networking traffic from ATT if people are curious). The problem is mitigated right now but we'll need some time to get normal connectivity (latency) working again for ATT customers.
We apologize for the inconvenience.