Hi,
The rule seems okay to me, what worries me is that you can't ping the device through public IP, could it be that you don't have public IP or that ping is forbidden in firewall rules?
Please check if you can at least ping the RUT240 public IP first without the forwarding rule, if you can - then try to forward it and see if SSH possible.
If still not, try to forward the ping rule instead and see if you're able to ping the local device connected to RUT240.
EB.