Google+ Hangouts video chat won't connect over AT&T

If you have a smartphone connected to AT&T, you just got a bit more incentive to hop over to WiFi whenever possible. The new Google+ Hangouts app group video chat feature appears to be disabled whenever you attempt to connect via the cellular network. We tested the feature using a Verizon handset as well -- we were able to stream video just fine. It's not entirely clear whether AT&T has specifically blocked access to the service, but regardless of the reason, we're all too familiar with the carr...