When trying to make a call with Sell Voice, I am unable to make a call and see the error message: Failed POST (402 error) /apis/voice/api/twilio/bridge.json
The error message often occurs when an account has run out of Voice credits. An admin can add more credits to allow everyone to make and receive calls.
If an admin checks the amount of Voice credits in the account and they are not empty, contact Zendesk Customer Support for further assistance.
For more information on other known issues, see this article: Troubleshooting Sell Voice problems.