You need to troubleshoot the issue

A company has an Office 365 tenant and uses Exchange Online and Skype for Business Online.
User1 is scheduling a Skype meeting with User2. User 1 is not able to see availability information for
User2.
You need to troubleshoot the issue.
What should you use?

A.
Microsoft Lync Connectivity Analyzer Tool

B.
OCSLogger

C.
ClsController

D.
Remote Connectivity Analyzer

Explanation:
Centralized Logging Service (CLS) is a new feature in Lync Server 2013. It provides a mechanism to
enable/disable logging across all Lync servers in a deployment from a single interface and to search the
resulting logs from the same interface.
You specify what should be logged based on the scenario you want to investigate. The scenarios
supported are AlwaysOn, MediaConnectivity, ApplicationSharing, AudioVideoConferencingIssue,
HybridVoice, IncomingAndOutgoingCall, VoiceMail, IMAndPresence, AddressBook, DeviceUpdate,
LYSSAndUCS, CLS, SP, WAC, UserReplicator, HostedMigration, MonitoringAndArchiving, LILRLegacy,
LILRLYSS, MeetingJoin, RGS, CPS, XMPP and CAA. Centralized Logging Service in Skype for Business 2015
https://technet.microsoft.com/en-us/library/jj688145.aspx