NPM to OMV Workbench returns "502 Bad Gateway " via HTTPS

I got nginx-proxy-manager working via Compose it points to deluge and NPM using a duckdns subdomains and letsencrypt, for both of these apps I'm able to reach them in their own subdomain with a valid letsencrypt certificate and HTTPS so I know npm is working but when I try to point to OMV's workbench, both on port 80 and changing the port to something like 8888 I keep getting "502 Bad Gateway", not sure why. I'm able to reach it via HTTP though using the domain set for it in npm. I've tried both enabling https on workbench and disabling it, enabling it can cause it to not be reachable, omv-firstaid has been very helpful in getting access back! That didn't happen before I set npm... anyways, how can I get NPM to point to workbench properly via https? All access is done locally.

---
version: '3.8'
services:
  app:
    image: 'jc21/nginx-proxy-manager:latest'
    container_name: nginx-pm
    ports:
      - '80:80'
      - '81:81'
      - '443:443'
    environment:
      X_FRAME_OPTIONS: "sameorigin"
    volumes:
      - ${SSD}/apps/nginx-proxy-manager:/data
      - ${SSD}/apps/nginx-proxy-manager/letsencrypt:/etc/letsencrypt
    networks:
      - network1
    restart: unless-stopped
    extra_hosts:
      - "host.docker.internal:host-gateway"
networks:
  network1:
    name: applications
    external: true

Quote from chente

You just have to make sure that the ports used by the OMV and npm GUI are different. Since npm requires ports 80 and 443, even though there are other ways to do it, the easiest thing to do is to change those two ports to different ones in the OMV GUI.

Right now it's different unless I'm missing something.

Is there an additional setting I should be changing?

Quote from pkordolian

So now you have 8888 for HTTP, in HTTPS (if ON) you still have 443

P.

Are you stating a fact or suggesting a fix? Https is off in omv workbench but the proxy is supposed to be the one to provide https. Enabling https in workbench didn't actually fix it in the past is that what you are suggesting?

Quote from chente

If you are accessing the GUI on port 8888 over http you don't need anything else.

What is host.docker.internal:8888?

That's how I point to the host (omv) since npm is running as a docker container (see docker compose yaml in first post). How else can I point to the host from npm?

I created a docker network for all of the containers whose access is going to be managed by npm so they're all on the same network. No external access is being granted to workbench!

Quote

In any case, if what you want is for npm to point to the GUI interface, you simply have to write the IP and port of the GUI in those host fields in npm. That should send you to the GUI.

Yeah I was being an idiot eventually I managed to figure this out yesterday. Not sure why I didn't try it, for some reason I assumed it wasn't available to the proxy even though the network is bridge :facepalm:

This issue has been solved. Thanks!