Trouble loading web site of a receiver so I can rename it so Siri can understand it on home network

I used to be able to get to a stereo receiver web page using its web address. But the past few years, it has been impossible to get to. The browser progress bar just goes a little and stops. I need to change its very long name so I can use it easier with a HomePod and Siri. It is currently something like “XYZ-4598 9878965”. I want to rename it “guest room AVR” via its web page. I did it once before. But it went back to this odd name. Anyhow…

I brought the stereo receiver address up in Terminal and got this odd thing:

(10.0.1.xx) at (incomplete) on en0 ifscope [ethernet]

(I Xed out part of the address)

What does this incomplete mean?

When the problem began, maybe 5 years ago, I had it ethernet connected strait to a switch and that to my router. I have many other devices on that switch that did not have any problems. The new receiver on that same switch has a web site and it works great. So the issue is not that switch.

Recently, I moved the receiver to another room, same network, but now have it coming out of an AirPort Express (which is on ethernet as an Airplay device only, Wi-Fi is turned off). The Express is essentially a one plug switch for it.

So that is two different places over years. The problem of its web site not loading remains.

What is happening?