RV320 can't be used in Router Mode

[ParamjeetSinghDhaliwal87381]

I have RV320 I want to create an separate network with 50 Computers which can talk in between and can get internet access from the ISP router which is on top of it, this works if I leave the router in gateway mode (Cisco Router) but as soon as I switch it to the Router mode my 50 computers loose the access to the internet, any Suggestion?

[Olamideharrison]

Cisco RV320 can work in either "Gateway" or "Router" mode. Manual says the following about the "Router" mode

I quote...Choose this mode if the device is on a network with other routers and another device is the network gateway to the Internet or this network is not connected to the Internet. In Router mode, Internet connectivity is available to the network devices only if you have another router that functions as the Gateway. Since firewall protection is provided by the gateway, disable this device firewall.

I connect WAN port of RV320 to LAN port of a cable modem. The modem works as gateway and router on 192.168.0.0. RV320 is on 192.168.1.0 and it shows that it got 192.168.0.13 from the modem. Modem does not show that address among connected devices however.

RV320 cannot ping any internet address while modem can. Any computer connected to RV320 gets valid IP and windows even shows that network has internet connection, but there actually isn't any. For some reason RV320 manages to resolve DNS names, however.

I tried disabling firewall, Ipv6 etc to no avail.