I can't connect to the Windows-based computer

Cause: The Windows-based computer is not set up to accept remote connections.

Solution: Turn on the remote desktop setting on the computer that you want to connect to.
Solution: Make sure that Windows Firewall allows exceptions for Remote Desktop.

Cause: The Mac cannot connect to the network.

Solution: Make sure that the Windows-based computer is turned on and is connected to the network.

Cause: Network policy is blocking connections.

Solution: Contact the network administrator about your organization's security policy.

Cause: The Windows-based computer can't be found.

Solution: Check that network settings on the Mac are configured correctly for the type of connection that you are using.
Solution: Verify that you have entered the correct computer name.
Solution: Use the computer's IP address if you can't connect by using the computer name.
Solution: Make sure that the Internet connection on the Mac is working.

Cause: The identity of the Windows-based computer cannot be verified.

Solution: Check that the Remote Desktop Connection security preference is compatible with the version of Windows that is running on the Windows-based computer.