Since you are using a Comcast connection which is a cable, the router requires a registered MAC address to work.
try to verify first with your service provider what is the MAC Address the is registered under your account. Then once acquired, access the router GUI (192.168.0.1) then go to basic setup. Set the Internet Connection to Dynamic. You'll see a clone MAC Address button (in older D-Link routers) but I am sure there is a field there that you can fill the MAC Address. Fill it up with the registered MAC Address so that the router can present a valid MAC Address to the ISP once authentication commence. Once setup, go to Status page of the router and check for WAN IP Address.
But before you go to the status page of the router, ensure that you save the settings on the router properly together with the proper connection such as the modem to the WAN port of the router