Microsoft Lync




Call Cannot be completed

This is one of the problems encountered from time to time. Usually the problems shows up when I have forgotten how I solved it the last time. So this time around, the problem gets page on site. One of my users was failing to make Lync to PSTN calls. In all the previous cases, the users could make PSTN calls but could not receive calls from PSTN. The cause was duplicate numbers. This normally happens when two support agents assign the same number to two different users on the same day and most likely same time. 

Really is it possible in Lync to have duplicate numbers. Yes it is very possible. If you run Lync in a small domain then this might not be an issue for you. However for the guys out the with multiple domain controllers spread across the globe where replication is sometimes a pain (1min is a pain). You will most likely encounter this.  

 So the question is why did this call fail.

To answer this question, I enabled logging on the Lync client and asked the user to make a call. After the call failure, I collected the log and set on my mission using snooper to confirm my suspicion. Below I noticed the call failed because it was forbidden

Details of the error indicated error below and immediately I knew duplicate number had been assigned.

 ms-diagnostics: 4002;reason="Multiple users associated with the source phone number


Locating the duplicate number

Lync control panel is not helpful in locating duplicate numbers, most likely because this is not expected. Instead I used Lync control panel to identify the number assigned to my customer Funeka. That number is critical for the next step to find out who else was assigned that number. So I turned to dsquery and ran the command below to locate the duplicate assignment.


dsquery * domainroot -filter "(&(objectCategory=Person)(objectClass=User)(msRTCSIP-Line=tel:+27xxxxx5689*))" -attr sAMAccountNAME msRTCSIP-Line -limit 0

Powershell fans the command below requires activedirectory module

get-aduser -ldapfilter "(&(objectCategory=Person)(objectClass=User)(msRTCSIP-Line=Tel:+27xxxx5689))" | select samAccountName,Name 

The one below is for those using lync server management shell

get-csaduser -ldapfilter "(&(objectCategory=Person)(objectClass=User)(msRTCSIP-Line=Tel:+27xxxx5689))" | select samAccountName,Name 


At this point the duplicate entries were printed out and I immediately went to my Lync control panel and reassigned a new number to one of users identified.

Who has been here?