Verizon Conditional Call Forwarding No Longer Working

Question

I have Google Voice calls forwarded to a Verizon cell phone (previously AT&T). We had conditional call forwarding set up and working on the AT&T cell phone, and again when we switched to Verizon several weeks ago. As of today, we discovered that the Verizon conditional call forwarding is no longer working. 
We have turned off/re-enabled conditional call forwarding multiple times and to multiple numbers (Google Voice and regular cell phone lines). We confirmed that total call forwarding works. We are using *71 for conditional, *72 for total, and *73 to reset.
We've reported it through the Voice app, and we're going to raise an issue with Verizon as well. Hoping someone has some ideas here.
The Google Voice line is a health care provider line--calls need to be forwarded back to the provider voicemail.

Bluescat · Accepted Answer

OK, great; I just wanted to be sure I understood your situation.
The other thing I mentioned is:  if you followed my instructions, which were not meant to be the solution, but problem isolation steps, you would have left that Google Voice number without the provider's cell phone number linked.  CCF back to the GV number won't work that way, so after you resolve the Verizon issue, please work with the provider to re-link her mobile number via a verification text message.
There is one other thing to check:  if the provider's cell phone is an iPhone, it may have Apple's relatively new "Live voicemail" feature enabled.  This feature breaks CCF, and so it must be disabled in the phone's settings.

Bluescat · Accepted Answer

Hi Stu Topp:  thanks for posting in the volunteer user-to-user Google Voice Community forum.
We need to do some problem isolation. 
Use a laptop or desktop computer's web browser, not a tablet or smartphone.  Sign into the correct Google (Gmail) account that holds your Google Voice phone number, and go here:  https://voice.google.com/settings.  Confirm that you see your Google Voice phone number at the top of the page.  If not, then you're signed into the wrong Google account.
Assuming this is the correct account, delete ALL of the devices and linked numbers, except for the "Web" device, which supports browser VoIP calling.  Call the Google Voice number from some unrelated phone number, and confirm that it rings to the Web browser client, then forwards to its Google Voice voicemail greeting after about 30 seconds.
Assuming this works, delete the Google Voice app from ALL previously linked devices and reboot them.
Using one Android or iPhone on Verizon, enable Conditional Call Forwarding to some other, non-Google Voice phone number.  Call the Verizon phone number, let it ring, and confirm that it forwards to the other phone number after 25-30 seconds.  If that works, power off the other phone, call again, and confirm that the call is immediately forwarded to that phone number's voicemail greeting.
Does all of that work properly?  If so, let me know.  If it doesn't work, you have a Verizon problem, and you will need to resolve it with them first.