Lync2010 UM integration failing with Exchange 2010

2017-12-11T17:16:47+00:00 March 21st, 2011|Exchange, Lync|

During a migration from OCS R2 to Lync I started having a problem when testing UM access to voicemail; displayed an error on call or redirect and disconnected. Ran some tracing and the following error was flagged in the diagnostics field:

MS-client-diagnostics: 52059;reason=”Invalid SDP in response”

Turns out this is caused by the VoIP Security setting  in the Exchange UM Dial Plan option. Whilst I used to have this configured as ‘SIP Secured’ when operating with OCS R2, it would appear it now requires to be ‘Secured’ to function correctly with Lync2010.

So, to fix: Exchange > UM Dial Plans > Properties of your Dial plan > VoIP Security = Secured

Hope this helps