This can mean so many things. Is your phone connected to Wi-Fi? Is the Wi-Fi network and your PC running VirtualBox on the same network. Can the phone "ping" the computer and the can the computer "ping" the phone?
If the answer to all of that is YES and you've confirmed connectivity, then it can ONLY be typos in what you're typing into the fields for the SMB connectivity. Everything has to be typed in exactly as it appears. No trailing spaces can be left on any words.