Stream Incoming Syslog Traffic Not Working On Port 9516 Despite Cloning Working Configuration

This message originated from Cribl Community Slack.
Click here to view the original link.

Is there a restriction on what ports I can use for incoming syslog traffic in Stream? I created a new one today on port 9516 and it will not come up. I deleted it, cloned a working config changing just the port to 9516, and again it did not work. I thought perhaps there was a restriction to stop me from using it, but the UI doesn't indicate any problem.