ALL (local) proxy hosts MUST be running or NPM doesn't start (no WebUI; affects VM usage)

Checklist

• Have you pulled and found the error with jc21/nginx-proxy-manager:latest docker image?
  • Yes
• Are you sure you're not using someone else's docker image?
  • Yes
• Have you searched for similar issues (both open and closed)?
  • Yes

Describe the bug

I use Proxmox LXCs and VMs often for testing. Some of these are proxied through NPM. Now with almost every NPM upgrade, it doesn't start, or at least shows no WebUI on port 81. Usually because I have shut down one or more (proxied) VMs.

The Docker log messages show something like nginx: [emerg] … (sorry, can't look it up anymore), and nothing more happens.

So I have to unnecessarily start up lots of LXCs and VMs just to be able to start NPM!

Could this possibly be changed, please? So it will start up even wwhen one or more local hosts are currently unreachable?

For the time being, is there a workaround? Like maybe disabling the currently switched off VMs in the NPM UI or something like that?

Nginx Proxy Manager Version

v2.12.3

To Reproduce
Steps to reproduce the behavior:

1. Have one or more defined proxy hosts locally unavailable.
2. docker-compose down
3. docker-compose up -d
4. This might be enough. If not, do a pull in between (like for upgrading).

Expected behavior

Normal start, possible upgrade migrations, and the WebUI available even when one or more local proxy hosts unavailable.

Screenshots

Operating System

Proxmox LXC

Additional context

Reproduce with docker-compose while a defined proxy host is unavailable, then inspect the nginx emerg log during startup. Confirm that Nginx Proxy Manager completes startup, runs migrations, and exposes the WebUI without requiring every local upstream host to be reachable.