The screen-dump is showing the details for int.23. That should be available and operational.
If you want to enable int.24 (that's your question, isn't it ?) could you choose 'port 24' on the dropdown box and post that screen-shot.
The issue will probably be that the 'physical type' for int.24 is RJ45, meaning that the RJ45 interface is configured to be the active interface for that combo-port.