We recently attended a customer who was having problems with their SOHO network. She was not able to see any shared folders on another laptop computer.
I tried restarting both laptops but that didn’t fix the problem. I then tried rebooting her router. After the router rebooted, all the shared folders became visible again!
Before you reboot the router, try shutting down the computer completely (rather than restarting) and booting it back up as that also fixes the issue in some cases.