For users using MS Office 2016 (Standalone) you need to install this version of Skype for Business.
Download the software from the MS Webiste
https://www.microsoft.com/en-us/download/details.aspx?id=49440
Select the file for the version of Office you are running, eg 64bit or 32bit
The top file is for 64bit software and the bottom file is for 32bit software
