Hi @Ian_Fok ,
We are seeing one Nucleus registered to your account, but it looks like even your other (working) Nucleus is getting some kind of network error.
Are there any more details you can provide regarding the network? What model/manufacturer networking gear do you have? Can you try to perform an OS reinstall on a different network? Your Roon OS (build 175) is quite old.
You would need to use two \ to connect via file explorer, for example:
\\192.168.171.71\