Additionally, you experience the following symptoms:
- Microsoft Lync 2013, Microsoft Lync 2010, or Microsoft Office Communicator 2007 R2 clients cannot participate in conferences by using the Lync Server 2013 or Lync Server 2010 conference modalities.
- Lync 2013, Lync 2010, or Office Communicator 2007 R2 clients that are not enabled for the Microsoft Exchange 2013 Unified Contact Store (UCS) do not display contact information.
Event ID 32042Log Name: Lync Server
Source: LS User Services
Date: 10/15/2013 4:02:05 AM
Event ID: 32042
Task Category: (1006)
Invalid incoming HTTPS certificate.
Subject Name: LyncFE01.contoso.local Issuer: Contoso-CA
Cause: This can happen if the HTTPS certificate has expired, or is untrusted. The certificate serial number is attached for reference.
Resolution: Please check the remote server and ensure that the certificate is valid. Also ensure that the full certificate chain of the Issuer is present in the local machine.
Event 61045Log Name: Lync Server
Source: LS MCU Infrastructure
Date: 10/15/2013 4:02:20 AM
Event ID: 61045
Task Category: (1022)
Description: The DATAMCU was not able to stay connected to the Front End over the C3P channel (HTTPS Connection).
The Web Conferencing Server failed to send C3P notifications to the focus at https:// LyncFE01.contoso.local:444/LiveServer/Focus.
Cause: The Front End may not be running correctly or may be unreachable over the network (broken HTTPS connection) from the MCU. Unavailability of The C3P channel affects conference controls, and can also prevent users from joining, starting conferences.
Resolution: Verify that the Front End server is running correctly and that network connectivity and an HTTPS Connection can be established between the MCU and the Front End server.
To work around this problem, set the Schannel registry key to a value of 0x0002 on all computers that are hosting Lync Server 2013 Front End servers. This change disables Session Ticket TLS Optimization in the system.
- You can disable this value without compromising the security of the system. The system will revert to handling TLS sessions exactly like the sessions were negotiated in earlier Windows Server operating systems.
- Lync Server 2013 is supported by Windows Server 2012 R2 when this registry workaround is performed.
- Click Start, type regedit in the Start search box, and then click regedit.exe in the results list.
- Locate the following registry subkey: HKLM\System\CurrentControlSet\Control\SecurityProviders\Schannel
- Right-click Schannel, and then click New DWORD (32-bit) value.
- Type EnableSessionTicket, then press Enter.
- Right-click EnableSessionTicket, and then click Modify.
- Change the existing value to 2, and then press Enter.
- Exit Registry editor.
- Open the Lync Server Management Shell.
- Run the following Lync Server PowerShell commands in the given order: Stop-CsWindowsService
Article ID: 2901554 - Last Review: Nov 24, 2014 - Revision: 1