Nucleus dropping off network every few hrs

My Nucleus is dropping off the network. This has been happening for the past few days. Seems to be getting more frequent. Music stops, all clients freeze. Nucleus webpage does not respond. Hardware reboot brings it back. The clients remember exactly where the music stopped, pressing play starts music up again exactly from where it stopped.

Generally playing from 2-6 hrs before failing.

Nucleus is connected from cable modem through a switch. I have tried different switches, cables, etc. I am testing now whether it only happens from Qobuz or my NAS. Most of testing has been through Qobuz.

I have re-installed operating system.

Update Sun Nov 28

I now believe that Roon (on the Nucleus) is simply crashing. At first I thought that something was going on with the network.

Crashes have become less frequent. Now every 12 hrs or so. I have reset most device settings. I also turned off any DSP. I connected a monitor to the HDMI. No messages after crashes.