A good source of information in troubleshooting any server issue is the event logs. Lync Server 2013 creates a dedicated event log for informational activities, warnings, and errors within the standard Windows Server Event Viewer console. To view this event log, following these steps:
1. Click Start.
eventvwr.msc and click OK to open the Event Viewer Microsoft Management Console.
3. Expand the
Applications and Services Logs folder.
4. Click the Lync Server log.
5. Examine the log for warning or error events, which might provide additional insight into any issues.