Seeing the user-interface.log Unable to get property '0' of undefined or null reference error when accessing the Spotfire server

Seeing the user-interface.log Unable to get property '0' of undefined or null reference error when accessing the Spotfire server

You have a clustered server deployment with a load balancer in front of the Spotfire servers. The issue occurs when two Spotfire servers are running and accessing the load balancer URL. The following have been checked:

• bootstrap.xml files
• server.xml files
• configuration.xml file 
• telnet to the TSS hostname and port is OK
• accessing the individual TSS URL is OK 

Look at user-interface.log, you may see the following:

2017-09-06T16:07:09,085-0400 ; ERROR ; com.spotfire.rs.tools.ErrorController ; 279c7f95-8815-1164-855a-9afa55242e6a: Unable to get property '0' of undefined or null reference
Current URL: https://tibcoPROD.com/spotfire/#/landingPage

  This indicates a persistence/session affinity issue with the load balancer. From the manual, there is this requirement: "You have obtained a load balancer that supports session affinity. (This means that after a session has been established, the load balancer can continue to route all requests from a particular client to a particular server.)". Work with the load balancer administrators to ensure that session affinity is always enforced.