Well it looks like the same issue occurs: 'The remote host closed the connection'
But now I know more about the issue, even when I don't specify a password--it doesn't even get to the point where the core prompts for it.
I'll see about setting up another server core to do tests, I'm presently running the core on a Raspberry Pi running Raspbian (since it runs 24/7, doing it that way just saves power). But I'm wondering if maybe it doesn't like the fact the Pi is not x86.