Teams Business Voice and extensions

Hi,

If you want to use Extension calling from an Auto Attendant it is the format +123456789;ext=789 you have to use.

Set up an auto attendant for Microsoft Teams - Microsoft Teams | Microsoft Docs

From a Teams client it is better to learn users how to call by name, ex. "/call <name>". But I guess you have desk phones that you want to use extension calling from, then in your Dial Plan you can setup this. But the extension have to match the number, so +123456789 would have extension 6789.

Use Extension Dialing in Microsoft Teams (ucstatus.com)