Metric data does not flow into Splunk despite setting up HEC Connection

Issue

Customers setting up an HEC connection https://docs.splunk.com/Documentation/Splunk/8.2.4/Data/UsetheHTTPEventCollector with Spinnaker Logging may encounter an issue where data is not being pushed to the connector

Cause

HEC connector with default ports uses 8088 or 8089 depending on the Splunk version by default.  This will happen if you do not configure a TCP listener, and can cause issues in Splunk with attaining data if the port is already in use