Consider the following scenario:
- The Conference Auto Attendant (CAA) service is deployed in a Microsoft Lync Server 2010 or Lync Server 2013 environment.
- More than one conference is scheduled at the same time.
- Multiple users dial in to CAA, and then join a public switched telephone network (PSTN) call of different conferences as a leader at the same time.
This issue occurs because the CAA service does not have a lock or other synchronization mechanism to deal with concurrent calls.