Lync 2013 Enterprise Voice error: 'The number you have called has been disconnected'

Working on a Lync 2013 Enterprise Voice deployment, we’ve recently cut-over a clients branch and found we had line URI’s and DID’s assigned two two users that were not working after their telephony setting was provisioned with Enterprise Voice.Every external call inbound would result in the error:

“Optus advises the number you have called has been disconnected”

We completed the following troubleshooting steps:

• We checked that the numbers were indeed available in the SIP service provider web portal
• We confirmed that the Cisco UBE router (acting as a mediation device between the Edge and Mediation Server roles with the SIP provider) was traversing the SIP traffic
  • CISCO-UBE-RTR#show sip-ua register status | s 612XXXXXXXX
    612XXXXXXXX -1 XXXX yes
• We checked there was no spelling mistakes or errors in the Lync Control Panel

All appeared normal and there shouldn’t have been the fault. I then went through notes and spoke with colleagues and found the source of the problem.

Thinking it through, the problem was a reuse of an existing number range that coincidentally we had chosen two numbers higher up in the range for initial pre-go live testing. So the problem was that Lync Server had the same line URI’s set to two different users. When this happens, Lync Server does not return to the Cisco UBE router or the SIP provider the correct response packets. Without going to far into Wireshark and packet tracing, bellow is a handy Powershell cmdlet that can quickly list all users line URIs making it faster to find duplicates:

Get-CSUser | Where { $\_.EnterpriseVoiceEnabled } | Select-Object DisplayName,LineURI | Export-CSV C:\\\[path to a valid folder\]\\lineuri-export.csv

Simply edit and add in a valid path to a folder, for example C:\Lync\export.csv and you will have a quick and easy means of searching for duplicate line URI’s.