"Request failed with empty response" connection error in Spectrum Enterprise Designer

Products affected: Spectrum Technology Platform, Enterprise Designer
 

Issue

In Enterprise Designer when 'Read Spatial Data' is selected an error message is encountered:

"Request validation failed. Request failed with empty response".

In this example Spectrum is installed on a cluster. 

Cause

The spectrum-container.properties 'spectrum.runtime.hostname' and 'spectrum.runtime.port' were not configured correctly. 

Resolution

UPDATED: March 18, 2020
The spectrum-container.properties file contains the properties that configure a cluster. In this case the following 2 properties were not set correctly and therefore the reason for the error.:
 
1) spectrum.runtime.hostname
Un-comment this property and set this property to the load balancer host name.
 
2) spectrum.runtime.port 
Un-comment this property and set this property to the port on which you have configured the load balancer to listen.Note: This property can be commented out, unless a distributed installation is used. For distributed installations, this property must point to all repository nodes.