Uninstall any VPN/Proxy programs that you have,make sure your firewall don't block any executable (.exe) files of the client,and that your antivirus don't delete/quarantine any of the client's files.
Your router's firewall could also be blocking it,you will need your IP to access it,open cmd.exe type ipconfig and copy-paste the IP shown in the "Default Gateway" into the address bar of your browser and check the firewall settings.