99.9 percent of the time it's down to the new router / modem. Different manufacturers use a slightly different IP range for their products.

If in doubt enable DCHP on the box then reboot both the receiver and the router / modem, they should re-pair with each other once they have rebooted. Then make note of the new ip assigned to your receiver and turn DHCP off so it does not change again or leave it on, it won't really matter unless you have lots of receivers / devices on your network.