Using "nvim scp:://user@hostname//path/to/file" but can't connect to the remote machine

I am trying to edit remote file through neovim by:

nvim scp:://user@hostname//path/to/file

An empty buffer is opened without asking for my password.
Upon writing to the file I get the following:

:!scp -q '/tmp/nvimd24gVl/2' 'user@hostname//path/to/file'
lost connection

shell returned 1

I read #8989 and found that :! do not support interactive commands.
But I don’t how to figure it out if I want to edit remote file through neovim. What is the correct way to do this?
nvim --version: NVIM v0.5.0-828-g0a95549d6
I am using ubuntu 18.04 in wsl.

:e scp://user@host//full/pathto/file should do the trick also :help scp

thanks for your reply. I try this but it reports the same things. :frowning:

Follow either SSH login without password or How to Set Up a Password-less SSH Login. You need to setup SSH without requiring a password.

thanks a lot! It works well now! ; )