Go to network settings in the Xeniu os.. be sure the IP address is set to DCHP and that the FTP server is on. Then shut off the xbox and plug it into your router. Repower on, go back to network settings, and check the ip address your router assigned the xbox. Use that to connect.
BTW, it wouldn't connect when you tried a direct connection to your PC because you are using a regular ethernet patch cable and not a crossover cable