Same issue started around 12pm pst today in the middle of a call. Call dropped and could not redial. Deleted and re-setup google voice twice. No change, problem persists. The setup works, meaning the account authentication to google is working. It's something in the routing protocols that's getting messed up.
Outgoing calls: error 403
Incoming calls: phone rings, but when answered there is nothing.
Google Voice services are up, as I can make/receive calls from my computers through the hangouts window.