Mobile calls not diverting to 121 voicemail - caller hears message “your call has not been connected …” message.

[WilliamChilds]

When my iPhone mobile call goes unanswered for 15 seconds - the call is not diverted to voicemail (which is set to divert to 121) - rather the caller is advised: "your call couldn't be connected, please check the number & call again".

Is there a code or set of symbols that I can input to enforce the diversion to 121? 

[BasilDV]

Hi @WilliamChilds 

The details on how to set your Call forwarding or Diversion is available here: https://support.tpg.com.au/mobile-voice-features#toc_4

Also, the details on how to set or enable your Voicemail is available on the same page.

Let us know how it goes.

BasilDV