I used to connect remote servers provided by Linode and GCP and I use Visual Studio Code via Sftp extension and all works just fine. However, with the same set of configurations, I couldn't connect to my Aws EC2 server. The following is the sftp.json (with sensitive information changed)
And the aws security setting is as following
The strange thing is that I can ssh connect to the server on the terminal and I can use filezilla to send file with the same credential as well. But somehow I can't connect to it via Visual Studio Code sftp or SSH remote extension.