After running my obi110 for some months now on GV, ran into this infamous, annoying, authentication error. Ugh. Checked, double-check, triple-check the login was right. I normally run expert config. No amount of editing the config directly would help. Neither would deleting the service in the OBI portal and re-creating it.
Something changed. GV or Obi, don't know.
I had to enable OBItalk Provisioning, THEN delete/recreate the GV Service profile in the OBI web portal.
Looks like my custom settings were wiped out though.
Hope this helps to save someone else time or frustration.
-MRTT
