Something went awry a few weeks ago with my LSX’s. When I got around to troubleshooting them, I ran through the setup and couldn’t get it to pick my mesh network, which is a problem b/c that’s the one that the other Roon devices are on, and I read somewhere that these LSX’s may not be mesh compatible.
In order to continue troubleshooting I decided to bypass the wifi for the moment and plug the KEF directly into the network via Cat6. Still not showing up as an endpoint in Roon.
I can play music through them using the KEF stream app.
Any help would be appreciated! 
A few things…
Let’s start with the mesh network set up. I have mine running on Google Wifi and have used the Spectrum’s Plume-based mesh network, as well. When setting up the LSX in the mesh, I disconnected all but the primary mesh node. So unplug the remote nodes on the mesh, try the wifi set up again and then add the mesh nodes back in. Also, use the cable between speakers if you are not. It does sound better and makes the speakers more reliable in any network.
When going to wired, you may need to remove the LSX from Roon and then rediscover them. Your wired and wireless networks may be addressing in different address pools and subnets.
Roon streams to the speakers. LSX Stream is telling the LSX where to pull a source off the web. Subtle difference. Depending on where you wire your LSX in, the streaming to method may not function across the segments of the network. Is the primary LSX wired to the mesh network’s ethernet ports or to your ISP router? Mesh networks set up their own addressing schemes behind the ISP’s DHCP.
Thank you so much for your reply. I will try and go through it line by line and troubleshoot.
Thanks again!