Hey @Steven_Bond,
Thanks for hanging in there through all of this, and for the detailed updates, they genuinely helped. I’ve now gone back through a fresh set of logs from your Nucleus, and I think we’ve finally found the real culprit.
The good news first: there is nothing wrong with your Nucleus itself. The hardware is healthy, your music database is fine, and the network cable to it is running at full speed with no dropouts. So this is fixable, and it’s not a fault with the Nucleus you’d need to replace.
Here’s what the logs show. Your Nucleus and your remotes and streamer need to be on the same subnet, the same local network range, so they can talk to each other directly.
Instead, your Nucleus is sitting on a different subnet from all your other devices: the Nucleus is on one network range, while your iPads, iPhones and Naim streamer are on another.
It can still reach the internet from there, which is why Roon ARC works when you’re out and about, but it can’t reliably see your other devices at home. That mismatch is exactly what produces “waiting for server” and “uh oh,” why it gets worse when a second device joins, and why a reboot only helps for a little while before it slips back. It also explains why typing in the IP address works only sometimes.
The most likely reason for this is that little booster disc you mentioned. If your Nucleus’s network cable runs into the booster (or into anything other than your main BT Home Hub), the booster can put the Nucleus onto its own separate subnet, which is what we’re seeing.
So before we change any settings, could you help me with one simple check? Follow the network cable plugged into the back of your Nucleus and tell me exactly what the other end plugs into, the main BT Home Hub, the booster disc, or something else.
A quick photo of both ends is perfect if that’s easier. That single answer will tell us whether this is a two-minute cable move.
The likely fix will be to plug the Nucleus straight into your main BT Home Hub (the same one your Naim streamer uses), so everything is back on the same subnet. I’ll walk you through it step by step once you’ve confirmed what it’s currently connected to.
We’re close on this one. Talk soon. 
