Call forward time-out than go to voicemail

[Tom Lee]

Good Afternoon Everyone,

I tried the call forward to a mobile phone. If no answer on the call forward, it will just keep ringing. If the mobile phone ignore the call, it will call again.
How to configure time-out than go to voicemail on the call forward?

 

[leejor]

What type of "call forward" exactly? Why is the caller not hanging up after it rings for a long time? I'd give it about 30 seconds, then try later.