400: Bad Request in HomeAssistant

So for some reason in v2021.7.0 HomeAssistant introduced a bug that breaks a lot of systems that rely on its NGINX reverse proxy add-on to provide ssl capabilities. Thankfully the fix itself is pretty simple. 

• To begin, try to navigate to the site to produce the error, then in the HAS web GUI navigate to the Supervisor Logs (Settings>System> Logs)

• Grab the IP that shows up in the error that reads 

  • "A request from a reverse proxy was received from XXX.XXX.XXX.XXX, but your HTTP integration is not set-up for reverse proxies"

• From here navigate to your configuration file in your chosen method (/config/configuration.yaml) where we will make edits.

• Add the following line, including the IP you grabbed from the logs

http:

  use_x_forwarded_for: true

  trusted_proxies:

    - XXX.XXX.XXX.XXX 

• Reboot the machine