You setup a number to forward to multiple users, and configured it with a custom Voice Mail, expecting that no matter what, if calls to that number are unanswered, that number’s custom Voice Mail will always answer. That isn’t always so, and here’s why:
There is a competition between turboDial and your users’ mobile phones for which Voice Mail answers first.
You can set the # rings turboDial waits and it will always wait that amount, and in the past you could be fairly confident knowing how long the mobile phone Voice Mail service would wait before answering (with some exceptions like phone powered off or in airplane mode).
BUT, with iOS 13 a new setting has arrived where a user can configure their mobile to block unknown callers. With that setting, unknown calls are sent IMMEDIATELY to Voice Mail. In those cases, the mobile phone wins the race even if you set turboDial to only wait a few rings.
What’s the solution?
Require users to set their mobile phones to NOT block unknown callers and never leave their phones powered off. Then turboDial has a chance to win the Voice Mail-answering race.