Docker remote host access from Windows 10, "Authentication failed."

How do I debug what is wrong with my setup?

Currently I have Windows 10, where I have a working Docker container made from
https://github.com/JetBrains/clion-remote/blob/master/Dockerfile.remote-cpp-env

I can access that from my powershell with
ssh user@localhost -p 2222
which asks for password, and gets to my container without any issues.

When I look at the running container log, sshd log clearly shows how my powershell ssh command has made the connection.

But when I create a Remote Host toolchain configuration in Clion 2020.2 (full details below), and in Credentials insert in
Host: localhost, Port: 2222
User name: user, Local port: <leave empty, says Dynamic>
Authentication type: Password
Password: password, Check ON Save password

... the "Test Connection" button states with a popup "Can't connect to remote host: Authentication failed.". sshd log does not show any trial connection to be happening.

CLion 2020.2.3
Build #CL-202.7319.72, built on September 17, 2020
Runtime version: 11.0.8+10-b944.31 amd64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
Windows 10 10.0
GC: ParNew, ConcurrentMarkSweep
Memory: 1987M
Cores: 16
Registry: run.processes.with.pty=TRUE
Non-Bundled Plugins: Batch Scripts Support, CMD Support, IdeaVIM, Docker, com.intellij.plugin.adernov.powershell