The first question is which one? Apache, nginx … I have nginx running which proxies the data to uwsgi which runs Tryton. Keep in mind that Tryton have to run on the root, so you maybe have to create a separate subdomain.
So generally speaking, you have a WSGI server which runs Tryton (NEVER use the development server in production!). If the WSGI server is working, you can connect the reverse proxy to it through a socket or port. You have to do configuration on the WSGI server and the reverse proxy server.
It can also be a firewall problem in the way that the proxy server is not exposed to the internet.
Search this forum with 'reverse proxy` and you get several topics about it.