OK solved the problem. I forgot that I have just changed my WiFi network to TP Link Deco X60 mesh network, and Deco X60 set itself up in router mode. So I had two routers managing the network. After manually switching the Deco X60 to Access Point mode, everything went back to normal.
very nice that the solution was simple and quick. it was great that you were able trouble shoot and quickly solve the problem with input from the roon community + support site.
please forgive me for respectfully using your experience to illustrate a point i made in an earlier post: this is a perfect example of the type problems folks have which ultimately are not a roon issue... even though initially attributed to roon. because roon software is the point of contact / control it is probably human nature to first assume any problem is with roon when in fact 99+ out of 100 such issues turn out to be caused by user networks, hardware, configuration, use case, etc.