Consider the following scenario:
- You deploy at least 3 front-end servers in a Microsoft Lync Server 2013 Enterprise Edition pool.
- You configure dial-in conferencing in the Lync Server 2013 environment.
- You apply the January 2014 cumulative update for Lync Server 2013.
- A public switched telephone network (PSTN) user tries to dial in to a Lync conference that is created in the environment.
Sorry, I can't find the meeting with that number
This issue occurs because the PSTN Conference ID mapping is orphaned in your SQL database. Therefore, Lync Server 2013 cannot find the Conference ID.