Folks, I have this same experience currently (no ringback on outgoing calls) but believe I may understand the catalyst - although not the solution. When I first set up the Obi200 with my GV account (actually my dad's GV account), it appeared to work correctly - with the exception of the lack of ringback. However, I subsequently found that his Google password had been changed and was unknown to him. So, the Google login to the Obitalk site was using cached credentials (and maybe not really authenticating against Google). I've since fixed his password and flushed browser cache and can use other Google services including GV without issue. I then deleted the Obi from his Obitalk confit, factory reset the device and started over. Once set up again, the unit worked fine EXCEPT STILL NO ringback on outgoing calls.
Ok, so, I did a full remove again and factory reset (device is on newest August firmware) and this time set the unit up on MY GV account (different Google account) and the phone then worked 100% correctly including audible ringback.
So, I did it one more time and still ended up with the lack of ringback on original account. I also did the steps recommended above by just switching Gmail accounts using that Replace link with same results (works for my account, no ringback for dad's)
So, I'm convinced that this corruption is tied to my dad's Obitalk account from the very first configuration. So, my next step is to find out how to DELETE his account from the Obitalk system and start from scratch. I would think that this would be easy...
Looking for ideas.