Hosting etherpad on port 0.0.0.0:9001
to then reverse proxied over a subdirectory path like app.domain.com/etherpad
has proven too tricky in Apache while it was so easy to accomplish in NGINX per their documentation here: https://github.com/ether/etherpad-lite/wiki/How-to-put-Etherpad-Lite-behind-a-reverse-Proxy#from-subdirectory-url