I was reading through this post, and found this small section that implies traffic to the home page should be getting redirected to Plinth (on purpose):
4.2.3. How to have a homepage on https://freedombox.local/ or the public IP
- The default page is set on your machine in /etc/apache2/conf-available/freedombox.conf (the RedirectMatch. You can can configure this file to make freedombox.local direct to a specific landing page. It will redirect any connections that don’t specify a /path.
I took a peek at /etc/apache2/conf-available/freedombox.conf , but the way this mechanism is implemented is a little beyond my grasp.
## Redirect traffic on home to /plinth as part of turning the machine
## into FreedomBox server. Plinth then acts as a portal to reach all
## other services.
##
RedirectMatch "^/$" "/plinth"
RedirectMatch "^/freedombox" "/plinth"
Probably best not to mess with it anyway–the file has a warning at the top that basically says “don’t touch!”
Can you try adding a /path to your domain, such as “share.mydomain.com/pastebin”?