Unable to add SSH connection to Virtual Linux System in local machine by Visual Studio 2019

Question

I am using VS 2019, and I have a Virtual linux system by Hyper-V in local.
I want to develop c++ by following "https://learn.microsoft.com/en-us/cpp/linux/connect-to-your-remote-linux-computer?view=msvc-170",
But no matter how I changed the configuration, It is still failed.
The error message pic as follows, it seems the ip or port wrong, I can confirm the linux IP, port,user name, pwd are all right, and I can use it succcessfully in xshell and console ssh

I have checked all the following links :

• "https://superuser.com/questions/1123552/how-to-ssh-into-wsl-from-windows-on-the-same-machine" ,
• "https://social.msdn.microsoft.com/Forums/vstudio/en-US/69075cf3-a1b7-4c4c-bbac-807e46426dc8/unable-to-add-ssh-connection-to-remote-system-in-visual-studio-2017?forum=vsdebug",
• "https://github.com/Microsoft/VSLinux/issues/132"

But the error is still exist. Search for help, thanks