I can not connect to my WiFi network.: You don't have a DHCP server in your network.
There are 2 different ways to run an IP based network. The easiest way is using a DHCP server, which provides automatically IP addresses. Most home gateways and routers provide this functionality. Refer to your documentation of your home gateway or router for details on activating a DHCP server.
An alternative way is to use static or fixed IP addresses. When you chose this option it is your own responsability to make sure all network devices have their own IP address.
To chose between static or automatic (DHCP) addresses, you will need to access your RC9800i's network settings.