Same problem / error message for me as @Jeffrey_Lane. Has started occurring recently after over a year of no problem, no change to network or set up as far as I know which is:
Virgin media broadband (350)
Hard wire to Linksys velop. Three nodes in house all hardwired.
Zenith hard wired into node2
Zenith = Roon core
iPad as Roon controller
OS 13.4.1
Roon version: 1.7 build 528
Yeah, was an accident! Emailed you just now - still getting used to how the roonlabs community works. Resolved, but needed reinstall of roon app on iPad. Rebooting zenith didn’t help. Thanks for your help. Richard