If the system (Rpi) has activated more than one IPv4 interfaces (wlan0 and eth0) Hyperion only offers the web confiuration tool with one (actually at me eth0) address.
Even if then the eth0 interfaces is deactivated (all eth0 configration entries removed) hyperion appears with this address, seems to take it from any cache files.
I think, the hyperion web configuration should should be available through all IPv4-addresses of the device. For more information look here.