The icon confirms that your server has been activated:
If you point to the icon, a tooltip like this will be displayed:
server LP5-SES-DSY (10.237.169.69) connected
confirming that your license server is up and running.
Note:
Once you have configured and activated your server as a standalone server, you can no longer change your mind and configure it as part of a failover cluster. That is why the corresponding options are grayed out.