For anyone who stumbles upon this old thread (as I did this morning) the process is now extremely easy and is in the documentation for the Add-On.
I struggled as did others at the time and the addition required in the add on documentation was the fix for me.
http:
use_x_forwarded_for: true
trusted_proxies:
- 172.30.33.0/24
I initially misread this and thought I’d need to put my own trusted local subnets in but this I imagine is the internal hassio addressing, notthing to do with your own home subnet(s).
Sorry if this has been answered somewhere else but I thought it may help some confused by the steps earlier in this thread.