Why won't Remmina connect to Windows 7 Remote Desktop?

I'm using Ubuntu and I'm trying to connect to another machine in a different network using remote desktop.

In Windows7 I have made the following in order to activate remote desktop:

1. I've gone to computer -> properties -> remote settings
2. I've selected the option: "Allow connections from computers running any version of Remote Desktop
3. I've opened "Windows Firewall with Advanced Security"
4. In inbound rules I've enabled the rules for remote desktop (public and domain)

I have also installed Remmina in the Ubuntu machine.

For configuring it I did the following steps:

1. Selected the RDP protocol
2. In the server input I have written the Windows machine public IP.
3. In username / password I have typed my login credentials (the same as my Windows admin account)

But when I try to connect I get this error message:

"Unable to connect to RDP server 89.130.251.160"

If I ping my Windows7 machine, I have a correct response.

Any suggestions?

Solution 1:

Make sure port 3389 is opened on your firewall and router.

In Remmina edit your connection, click the "Advanced" tab and choose RDP under the "Security" option and save.

Solution 2:

Just delete the server causing problem from the file ~/.freerdp/known_hosts and it will work.