Hi Rick:
I don't think your Google Home has anything to do with this. I have one, with calling enabled, and it isn't interfering with my inbound Google Voice-->OBi calls. Google Voice allows multiple connections to the same Google account, and the Google Home is (at this time) an outbound-only service.
Using a laptop or desktop computer web browser, not a smartphone or tablet, open an "Incognito" or "Private browsing" session (Ctrl-Shift-N for Chrome browser, or Ctrl-Shift-P for other browsers). Log into the Gmail account that holds your Google Voice number. Click Ctrl-T to open another browser tab, leaving the first tab logged in.
On the second tab, log into your OBiTALK web portal dashboard and click on your OBi. Click on the SPx that hosts your Google Voice number, and get past the 911 warning. Click the link to "Sign-in to the correct account, and then, Click Here to connect the OBi with your active Google Account".
Wait, then confirm that the SPx status is "Connected". Now, try calling your Google Voice number from some other number, NOT from one of your forwarding phone numbers, The OBi's phone should ring.