Not an expert but have you logged into the associated account (
https://google.com/voice) to check settings?
If you can't log in https://www.google.com/voice/account/recovery or
https://www.google.com/accounts/recovery/forgotusername
I had an issue for a while when I 'upgraded' to hangouts with one of my
numbers that stopped working; I had to downgrade it again.
Another time I had to set insecure connections to allow Asterisk to use the
account via chan motif.
I've only had the disconnected message when I failed to verify a google
voice account after not using it for a while.
You didn't mention what you were using the google voice with which was
failing.

JD


On Fri, Aug 31, 2018 at 6:01 PM Joe Lowder <joe@actionline.com> wrote:

> One of my Google Voice numbers has stopped working correctly and neither
> google nor the the google product forum is able to assist.
>
> I am willing to pay for expert assistance to resolve this.
>
> Calls to one of my two google voice numbers is continuing to work
> correctly.
>
> Calls to the second have worked correctly for several years, but within
> the past week, calls from land lines are now being answered with this
> recorded message, "That number has been disconnected ..." Voice calls
> from mobile phones to the same number are processed correctly. Text
> messages are also received and processed correctly.
>
>
>
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