Hi @Ramiz_Saei,
Sorry to hear you’re having issues connecting! As a next step, lets fully remove Roon from the windows and do a fresh install - do you have a recently saved backup?
After you uninstalled Roon, navigate to C:\Users\[*Your username*]\AppData\Local
and delete all Roon folders:
RAATServer
Roon
RoonGoer
RoonServer
After a fresh install, restore your recently saved backup to load your prior library settings.