SSH connection dropping immediately after authentication in Ammonite sshd

I realize this question (or similar ones) have been asked elsewhere, but the solutions haven’t worked for me. I’m trying to use ammonite in a scala/java project locally and start the SSH server with

    import ammonite.sshd._
    import org.apache.sshd.server.auth.password.{AcceptAllPasswordAuthenticator, StaticPasswordAuthenticator}
    val replServer = new SshdRepl(
      SshServerConfig(
        address = "localhost", // or "0.0.0.0" for public-facing shells
        port = 22222, // Any available port
        passwordAuthenticator = Some(AcceptAllPasswordAuthenticator.INSTANCE)
      )
    )
    replServer.start()

I am then able to connect and authenticate with ssh jbennett@localhost -p22222 (or any username, it doesn’t seem to matter, but I’ve read elsewhere using a user without a home folder can cause problems, so I use an existing username). Problem is after authenticating the connection immediately closes. Here’s the output of ssh jbennett@localhost -p22222 -vvvv: https://pastebin.com/DAZyxnBH

I’ve looked at /etc/ssh/sshd_config and everything is mostly defaults. I tried changing to use internal-sftp following one other suggestion, but that didn’t make a difference.

#old line:
#Subsystem  sftp    /usr/libexec/sftp-server
#new line:
Subsystem   sftp    internal-sftp

The full file is here: https://pastebin.com/0FcivDVf and the include line’s file contents is just

# Options set by macOS that differ from the OpenSSH defaults.
UsePAM yes
AcceptEnv LANG LC_*
Subsystem   sftp    /usr/libexec/sftp-server

Not sure if this matters for this use case, since the SSH connection is connecting to a REPL instead of a shell, but my login shell starts up fine for the jbennett user, so it doesn’t appear to be a problem with the shell profile, either.

Please let me know if you have any ideas on how to fix this!