I had an error message recently that appeared in the client logs for a user with Enterprise Voice enabled. The Skype for Business Client informed the user that the call could not be completed. This was the same for any call made.
Each time a call was attempted to the PSTN, the following message appeared in the client logs:
ms-diagnostics: 4002;reason=”Multiple users associated with the source phone number”
This error was meaningful and pointed me to the cause. It is telling us that two or more users have the same phone number assigned to them in the Skype for Business Control Panel.
Finding these users was easy with PowerShell!