I just installed a new vm of Debian from a netinst ISO, everything went fine.
But when I went into
/etc/ssh/ssh_config to change the PermitRootLogin setting to yes, it wasn't there, so I added it,
PermitRootLogin yes, then restarted ssh, tried to login, it failed.
Permission denied, please try again.
I'm using the right password, as I use it to log into the VM directly.