When attempting to add contacts to your Skype for Business contact list you receive the following error:
There are a number of different causes for this error, but the most common solution is to delete the SIP profile for the Skype for Business user.
To delete the SIP profile for a user on a Windows workstation, follow the instructions below:
1. Close Skype for Business completely by expanding the menu in the client next to the cog.
2. Select File > Exit.
3. Open Windows Explorer and navigate to the following folder:
%localappdata%\Microsoft\Office\15.0\Lync4. Delete the sip_username directory that matches the sip address of the user experiencing the issues. This directory will be rebuilt the next time Skype for Business client is restarted.
The SIP profile folder and cached information will be rebuilt and the issues above should be resolved.