What is causing these error messages?

A customer is unable to login to Agent Workspaces, and the administrator finds the following error messages in the log files.

2018-04-19 06:04:45,386 [WebContainer : 4] AuthorizationService ERROR C AuthorizationService-3.4.0.0.340003 C Caught exception while authenticating with data source: HR-LAB

javax.naming.CommunicationException: 135.35.67.19:636 [Root exception is java.net.ConnectException: Connection timed out]at com.avaya.zephyr.services.production.AuthorizationService.ldap.LdapDAOClientImpl.handleAuthenticationSystemException(LdapDAOClientImpl.java:116)

What is causing these error messages?
A . An LDAP connection issue was caused due to an incorrect LDAP parameter.
B . The session timed out due to a browser issue.
C . The Multimedia Cache database is unable to connect.
D . SMGR is not authorizing Agent to login.

Answer: D