The Windows host for EC 2 has Port 3389 open, but the console has been prompted to open 3389

Did you open the port in the security group? Do you have a NACL blocking the port? Where are you trying to access the host from?

Look at the following document with some possible solutions https://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/troubleshoot-connect-windows-instance.html#rdp-issues