Voicemail question

Good afternoon!

I am configuring my voicemail boxes for users. I have set internal/after and external/after to use the voice mailbox template, setting up 2 different arguments: busy and not answering. I can get the voice mailbox to trigger when the line is busy for the test user but not when for “Not answering”. It just rings and rings and rings. I set my stopwatch and stopped it after about 2 minutes of ringing. So, confirmed working on a busy line.

My question is with the not-answering. When does the voicemail determine “not answering” to happen? Is there a way to change settings for that particular argument, so the phone and voicemail know when someone is not available or not at their desk?

Thanks for input!