Probably happens when the main router crashes.
Since iMac and NAS are going through it, it is a big trouble in LAN.
The network will recover automatically, but Roon probably freezes due to the effect and cannot restart, nor can the iMac restart. It is the impression that I could not catch the error.
Just to clarify, your Roon Core is your iMac? When this issue occurs, your Roon Core freezes and does not respond as well? What exactly are you seeing? Perhaps you could record a short video of the behavior?
That’s right. Roon Core is moving on iMac.
And when the network is disconnected, it stops responding.
I usually run Roon Bridge on Mac mini. Also try to shoot video while Roon is running.
Please do send the video when possible. I would also check to make sure Roon is allowed past any firewalls you may have, you can use these instructions from Apple to do so. Thanks!