I am only posting this because none of the above answers helped me figure out that my config was actually fine to begin with.
When you use the splunk list forward-server is only shows you forward servers that are active in the instant you ran the command, so unless you are actively pushing data, none of your forward servers are going to show up as being "active". Once you are pushing data, you can also incorporate the watch command to auto refresh the command and catch an active forward: watch -n 5 splunk list forward-server ,Only posting this because none of the above options helped me discover that my config was fine:
A forward server will only show up as "active" using splunk list forward-server command if it is actively forwarding data. Run the command a few times and chances are you will see it move to the active state. You can also incorporate the watch command to auto refresh the command: watch -n 5 splunk list forward-server
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