Help with Port Forwarding Error

Port forwarding requires that the internal IP address remain constant. Rather than set a Static IP on the actual device, the recommended practice is to use the Orbi web interface, Advanced Tab, Setup Menu item LAN Setup to reserve (or 'assign') specific IP addresses to devices using their hardware Mac address.

The DHCP 'pool' of addresses to be handed out to other devices is set to a separate range of IP from those that are being reserved for specific devices.  With the separation, there is no chance that some device will be assigned an address from the pool that should be given to one of the fixed devices.