Please follow these steps to determine the cause of the error: https://gist.github.com/Eugeny/6038158

Thanks! I will add your example to docs

Most probably, $PATH for root and your user account differ

This means that you don't forward resource URLs: /ajenti:static/resources.css

The root access URL itself isn't prefixed, it's still https://<host>:8000

Hi Martin!

Please take a look at our NGINX example: http://docs.ajenti.org/man/reverse-proxy.html

You need to proxy URLs starting with "/ajenti", not only "/ajenti/":  I guess the correct configuration would be 

ProxyPass /ajenti http://localhost:8000/
ProxyPassReverse /ajenti http://localhost:8000/

I have separated Debian and Ubuntu repositories, so Ubuntu users should not have troubles with python-requests installation anymore.

1.0 beta doesn't show password change / plugin selection screens on start, are you sure you're running beta?

Yes, you can use nginx proxy_pass or similar function in Apache to redirect requests to your subdomain to 127.0.0.1:8000