This is most likely caused by the same issue preventing you from downloading the templates (Tomcat is unable to access certain files within the application).
Either there’s a simple file permission issue behind it OR there’s a fundamental problem with the way the standalone WAR (running the application within an embedded Tomcat process) handles resource files within the WAR file.
I can’t make any recommendations without seeing the output from the other thread, but eventually we might want to think about recreating your production environment using the “latest” version of the installation docs, which uses the standard approach of deploying the application to a standalone Tomcat instance.
I will try to replicate the issue locally when I get a chance.