Hi,
It could be that you're running same subnet DHCP servers on both devices. Make sure only one DHCP is active. You can try connecting RUTX11 to different computers to see if the issue is in RUTX11, as it works as a router normally, but when you connect another router - you must make sure any services or servers aren't running in the same local network.
Also, make sure you're running the latest firmware.
EB.