If you add a new device for the first time to the RMS it will always have a free license (1 month). So that is why you get license type: free. If you will remove the routers from the RMS the free license will be void. And next time a paid license will be used.
For why it is not working. You could try clearing your browser cache (Ctrl + F5). Or using a different browser. I have 6 routers added with free licenses and they are working just fine.
Or you could try turning it on/off. Using Top control menu - see a screenshot.
You can always find the correct port in the WebUI of your router. System / Administration / RMS.
And the port is: 15009