Hello,
This happens because you are trying to reach a LAN device from the WAN. Try connecting from your phone (make sure you're not connected to the RUTX11 WiFi) and everything should work well.
If you'd like to disable this error message, please navigate to System → Administration → Access Control and disable the "Ignore private IPs on public interface" option. However, it is recommended to reach the device with it's LAN IP address (e.g. 192.168.1.1), when connected to the device in question.
Port forward rules will also not work from the Public IP → LAN, when accessing the public IP from the LAN. To make them work, disable the Enable NAT Loopback option in all of the affected port forwards.
Best regards,
DaumantasG