I will try that this afternoon. Worth a try.
Have you checked, Ethernet ā Hardware ā Configuration set to automatic?
Yep, all fine and functioning,
Thanks so much. 18 hours later, my zones are holding. Fingers crossed that it will last. Thanks again.
Very interesting, thanks for the info. I hope it sticks! 
It was fine until i tried to use it.
I donāt know what, but something seems very wrong
Not sure how beefed up that 2012 is, but if you have 16GB of RAM (cheap and easy upgrade), it might just be all the Mac Mini you need. Is it a āLate 2012ā? (Thatās what you want.)
Thatās what Iām running, and itās been a flawless roon server for 6 years. Itās still on Catalina 10.15.7 and thatās the furthest it will go.
See if that works.
Iām not sure the exact vintage of my 2012. But it costs me nothing to do a recovery and see if it works. I am increasingly frustrated trying to use a software package ā Roon ā that I have enjoyed for years. If the 2012 woks properly, I will likely keep it in my system.
I will post my results here, this pm and tomorrow am.
Yeah. Thatās why I am firing up a 2012 Iāve had in storage for a while. I am interested to see what will happen. Donāt want to buy an M4 until I sort this out.
I have this problem on an M4 Mac mini. I too am forced to do this on a regular basis: āYou need to go to settings/privacy&security/local network and toggle the Roon entries off then back on. Then quit Roon server by clicking on the menu bar item and choose quit, then once Roon server has closed, reopen the Roon app. This forces Roon to rescan the network for devices. Your devices should then reappear (do for me every time)ā
It should be seamless, no hoops to jump through each time I want to access my music.
Used to be.
Well, I had forgotten how bad my 2012 had become. Not going to happen. Back to the 2018 and more fun and games.
Yes, I know this āworks.ā But it is a real PITA to make this a part of my morning routine. Time was, it just worked.
Not sure if Apple or Roon is the villain in this drama.
Iām having this problem too. I upgraded to an M4 with a fresh install of roon (no migration) and it did not solve the problem.
The boat weāve found ourselves in gets bigger.
Use Windows (Ducks under Desk) 
I have since Windows 3.1 with no regrets , I gave up Apple at the Apple ][ when it constantly ate my Apple Pascal 5.25 floppies , simply couldnāt depend o the OS not to delete files.
Much later I started development in.NET so I was stuck to Windows.
But seriously in my experience, Roon is rock solid on both Windows and ROCK !!
Well donāt let windows users advise on how to solve this. And hopefully you didnāt reinstall the OS or (god forbid) buy a new computer. Iām on the latest version of Sequoia as well and yes with each of the last few updates of either the OS or Roon my local audio devices disappeared. In each case I was able to fix it by closing the app on the Mac which is acting as my server and also the remote Mac which is experiencing the issue. Possibly also with a computer reboot but Iām not certain thatās necessary or helpful.
This is annoying but it doesnāt require evasive action nor the nuclear option.
Has Windows treated you so badly 
Yes with Windows More Errors ehm Millennium Edition.