If you're using the Call Flow Builder, you can activate a setting that prevents voicemails and automated systems from answering a call. This ensures that a personal voicemail on a destination number does not interfere with your call flow. You can also use this setting to prevent an automated system on a destination number from interfering with a call flow you've created.
Once this setting is active, agents who answer a call will hear a message prompting them to press 1 to be connected to the caller. If they press 1, they'll be connected to the call. If they do nothing, then the call will route through the remaining call flow steps. The caller won't hear this prompt, only the agent.
If an IVR system is answering the call on the destination number, this feature should not be enabled, since the IVR will be unable to press 1 to accept the call. This will prevent callers from reaching your business.
Once your call flow is updated, we recommend placing a few test calls from a telephone number that's not included in your call flow to ensure your calls route as expected.