A lot of newer installs will automatically prohibit the root user from logging in directly, for security reasons or they will only allow key based access.
If you know what you are doing/don't care about security or have an incredibly secure password for testing, then you can enable it.
Edit this file: /etc/ssh/sshd_config
Find the following line: PermitRootLogin
Set it like this:
PermitRootLogin yes
Now rest........
I keep getting messages like this shortly after using the proxy (it works for a few seconds/page loads and then stops):
channel 12: open failed: administratively prohibited: open failed
I'm not sure what the issue is unless there's some kind of hardware firewall on the other end. I've used this exact configuration on multiple servers with no issue and even disabled iptables etc..........