I have one of the comcast routers that was installed with my X1 box. Per the router info it's a Cisco Model DPC3939. It supports both 2.4 and 5 GHz. Make sure you are connecting to the 2.4 GHz not the 5GHz (Chromecast help page says 5GHz is unsupported). I tried rebooting router then chromecast, that didn't work. I tried adding the mac address manually to the router and was still having trouble (router saw the chromecast as connected but during chromecast initializiation it couldn't connect to the newtork). What finally fixed it for me was fiddling with the UPnP settings then rebooting the chromecast after. You can get to the UPnP settings by logging into the router, then: Advanced > Device Discovery These are the setting I have, that worked: UPnP: Enable Advertisement Period: 5 minutes (default is 30) TTL: 10 hops (default is 5) Zero Config: Enable (default is disable) After saving those settings I then restarted the chromecast and went through the connection initialization on the chromecast app and it now connects / works.
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