A 500 Worker error is seen when opening Monitoring & Diagnostics > Instances > Web Player on the Spotfire Server Administration interface. In server.log, the following error is seen:

ERROR 2017-02-02T10:57:19,109+0100 [] server.jsp.error: An exception occurred (ID: ab3b97e5-2d41-471e-94df-ab709bc82224)
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.web.client.HttpServerErrorException: 500 Worker error id: 345a8ea7aa34427ab70fe34d7367c02c (Value cannot be null.%0d%0aParameter name: source)

1. Export the configuration currently used for the Web Player service (see export-server-configuration).
2. Open the Spotfire.Dxp.Worker.Host.exe.config 
3. Search for setting name="AllowedFilePaths" which should be within the <Spotfire.Dxp.Data.Properties.Settings> section:

   <setting name="AllowedFilePaths" serializeAs="Xml">
           <value>
             <ArrayOfString>
               <string/>
             </ArrayOfString>
           </value>
         </setting >

   • If that section is commented out by being enclosed by <!-- and -->, remove the <!-- and --> to uncomment out that section.
   • If that section is not present, insert it inside the <Spotfire.Dxp.Data.Properties.Settings> section.
4. Save the file.
5. Import the configuration (see import-service-config).
6. Assign the created configuration to your service.
   • Option 1:  In the command-line interface, assign the created Spotfire Web Player configuration to the Spotfire Server to make it possible to use for the service:
     set-service-config --service-id=value --config-name=WebPlayerConfiguration
   • Option 2: In the Spotfire Server web interface:
     - Nodes & Services > Nodes > Select your service on the left > Click Edit
     - In the 'Edit service' dialog, select your imported configuration in the "Configuration" dropdown.
     - Click Update (Note: This will trigger a restart of the instances).

• https://docs.tibco.com/pub/spotfire_server/7.11.1/doc/html/TIB_sfire_server_tsas_admin_help/GUID-958A3AB5-7243-4837-9AEA-78AA274A6F7E.html