The receiver most likely uses DLNA or another L2 discovery protocol. The only way to get them to work would be to ensure that all the devices are in the same L2 segment (same VLAN), same SSID (some Chromecast apps actually check the ESSID name even though it doesn't really matter) and you'd need to turn off drop broadcast and multicast.
The best thing would be to wait because you won't have to make any of those changes, "It just works".