You may encounter the following issues in a Microsoft Lync Server 2013 environment:
When a public switched telephone network (PSTN) user tries to dial in to a Lync conference, the user receives the following error message:
Sorry, I can’t find a meeting with that number.
Lync clients cannot retrieve conference data.
To resolve this issue, install the following cumulative update:
2987510 September 2014 Cumulative Update 5.0.8308.815 for Lync Server 2013 (Front End Server and Edge Server)
Note After you install this update, to recover the lost conference ID, you must contact Customer Support Services.