EndpointServer service for an Endpoint detection server stuck in Starting state

Products

• Data Loss Prevention Enterprise Suite
• Data Loss Prevention Endpoint Prevent
• Data Loss Prevention Endpoint Suite
• Data Loss Prevention Endpoint Discover

Issue/Introduction

You may see some Endpoint Prevent detection servers are stuck in the Starting state, with specifically the DLP subservice EndpointServer being the one that is stuck. All other subservices are in the Running state. 
The Enforce Console may report Server Status Error 1101: Aggregator failed to start

The one of the following can be also seen in the Aggregator log around the time of the server startup attempt:

WARNING: (ENDPOINT_SERVER.3) Endpoint Server failed to start
java.lang.InterruptedException
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:998)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1304)
    at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:231)
    at com.symantec.dlp.communications.applicationcommunicatorlayer.MonitorControllerCurrentTimeProviderImpl.waitToResetMCCurrentTime(MonitorControllerCurrentTimeProviderImpl.java:61)
    at com.vontu.aggregator.Aggregator.waitToCompleteMonitorControllerHandshake(Aggregator.java:709)
    at com.vontu.aggregator.Aggregator.start(Aggregator.java:669)
    at com.vontu.aggregator.Aggregator.start(Aggregator.java:646)
    at com.vontu.aggregator.Aggregator.initializeAggregator(Aggregator.java:311)
    at com.vontu.aggregator.Aggregator.main(Aggregator.java:217)

Or

com.vontu.aggregator.Aggregator waittoCompleteMonitorControllerHandshake
INFO: Waiting for handshake with monitor controller to complete...

Resolution

The above log exception says that Aggregator subservice on the Endpoint Prevent has attempted to handshake with the DetectionServerController service on Enforce, but the handshake did not complete successfully. Aggregator needs to complete that handshake to complete its startup. 

It is recommend to perform a two-sided restart of the DLP services:

-Symantec DLP DetectionServerController on Enforce

-Symantec DLP DetectionServer on the EP detector

Do this for all affected servers where EndpointServer subservice is stuck at Starting. After a couple of minutes, check if all detectors are able to complete startup and are in the Running state.