NoRulesJustFeels

The virtual network interface 192.168.56.1 is confusing the current logic for picking the network interface to communicate with your Chromecast device. Try shutting down that interface.

You didn't set your app Id.

https://developers.google.com/cast/whitelisting#whitelist-receiver

You have to host a copy of the receiver index.html file on your own server and then send that URL to Google for whitelisting the device and get the app...

Provide the debug output by running Fling from the command line: java -jar fling.jar

If you can't get to port 9222 the the device isn't configured correctly. Make sure you have enabled sending the serial number to Google.

Restart your Chromecast device to make sure the serial number is sent to Google.