Thanks Daniel. My Roon nucleus is now CONNECTED and functioning after 10 days! Thanks to you, Jamie and Noris, and also Deniz with Evolution Audio/Video in Fairfax, VA, who sold and set up my Nucleus four years ago and provided me help with the final fix to get it back online. I had eliminated one of two Netgear switching boxes around day 6 as it only housed the ethernet connection to the Nucleus and I was trying to simplify things. I restored as at Deniz’s suggestion about an hour ago and voila! My router and the Nucleus reestablished communication.
So glad to have Roon and my library back!
Bruce