Windows confirmed that "%1!s!" is currently online, but is not responding to connection attempts at this time. This usually ...

Windows confirmed that "%1!s!" is currently online, but is not responding to connection attempts at this time. This usually means that a firewall is running somewhere between the two computers and is blocking "%2!s!".  Windows has confirmed that Windows Firewall on this computer is correctly configured to allow this connection. However, a remote firewall might be blocking your connection.