Google Voice is not down, nor has it been. Yes, you have the last-available firmware version (the device is now at end-of-support-life, and that will be the final firmware version).
It's more likely that you set it up improperly on your OBi, perhaps while logged into the wrong Google account.
Open a laptop/desktop computer web browser, not a mobile device browser, and go to the "legacy" version of Google Voice settings.
https://www.google.com/voice/b/0#phonesLook at the left side of the web page. Do you see the
exact two words "Your number", and underneath it is your inbound Google Voice number? If so, you are logged into the correct account. If not, this is the wrong Google account, and you need to find the correct one. If this is the correct account, then single-click the gear icon in the upper right corner of the web page. Look at the email address it shows.
Leave this browser tab open. Click Ctrl-T to open another browser tab in the same web browser. Go to the OBiTALK web portal. Click on SP1. Go to the main settings page, and look at the "Active Google Username". Is it exactly the same as the Gmail account you see on the Google Voice browser tab? If not, you set up the OBi with the wrong account. Click the link next to "Replace Google Account Credentials" and then follow the instructions to re-configure the OBi with the correct Google account. Make sure it is set as the primary line for outgoing calls, and then submit your settings.
After the OBi reboots, try your call again.
