Article ID: 873188
If you turn on Windows Firewall and then select Allow this computer to use a network scanner in the Scanner and Camera window in Control Panel, you cannot use the Scanner and Camera Wizard to access a network scanner.
This problem occurs because Windows Firewall blocks TCP port 21. This port is required.
To work around this problem, you must create a Windows Firewall exception for TCP port 21. To do this, follow these steps:
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.