Hi are you able to log into balenaCloud and see the device online and see that all the services are running? If so can you try what Anton suggested above and open a web terminal to the host container on the device and running the curl commands to ensure the mc-server container is functioning correctly? We should probably rule out that everything is functioning correctly first before trying to debug any network issues. Also, can you confirm the model of Pi you are using, as I note that the instructions say the 1GB variant will not work.