I have similar problem right now.
Except that I am running Wordpress on Debian container on Proxmox hypervisor.
I am getting Bad gateway error 502 when I try to access my domain in browser.
(https://www.reddit.com/r/selfhosted/comments/12chm92/bad_gateway_error_502_for_selfhosting_wordpress/)
This is my post on Reddit so I don’t need to write all things again. If somebody could help 