Q: I enabled Allow remote connections to this computer in the System Properties of my non-domain joined computer, so why can't I connect?

A: When Allow remote connections to this computer is enabled, the firewall exception to allow communication is automatically enabled. However, there are different types of networks: domain, public and private. When the setting Allow remote connections to this computer is enabled, the firewall exception for the domain network is enabled but not the exception for the Public network. If a machine isn't domain joined, then its network would be Public, therefore you'd need to perform the following to allow remote desktop:

  1. Log on to the computer.
  2. Open the Windows Firewall with Advanced Security MMC snap-in.
  3. Navigate to Inbound Rules.
  4. Right-click Remote Desktop, User Mode (TCP-In), where the profile is set to Public and select Enable Rule. Repeat for Remote Desktop, User Mode (UDP-In), where the profile is set to Public.

You should now be able to connect.