SIP Error 485 Ambiguous

Posted by erwin on Wednesday, June 7, 2017


A customer was facing the problem that it was not possible to reach a certain contact person on his E164 number.

The first thing to check was in this case the Audiocodes Syslog Viewer. What is happening with the call? Does the call reach the Mediant or Skype for Business Server?

So i called the number from my own Skype for business Client. I received the following error.

Let’s check the Syslog Viewer:

The first thing i saw was the 485 Ambiguous SIP response from the Skype for Business Mediation role.

Fire up Powershell with the script from Andrew Morpeth (Lync Get All Assigned Numbers), This script will export all objects with a LineUri to CSV. Make sure you edit the location in the script, by default it will write in C:/ Root.

Go to the location and open the CSV file with Excel or any other editor. Search for the number and you’ll see what is causing the problem. 2 Users where assigned with the same number.

Remove the number from one of the users and your problem is fixed.

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