Redirect & SSL Issues with Nginx Proxy Manager and Virtualmin Setup


I’m currently facing a challenging issue involving Nginx Proxy Manager (NPM), Virtualmin, and SSL certificate configurations for two domains I manage: and I have set up NPM to manage my reverse proxy needs and Virtualmin for web hosting management. Here are the specifics of my setup and the problem I’m encountering:

Domain Setup: is hosted on a server managed by Virtualmin with an internal IP of It serves a WordPress site and is accessible and working fine. is supposed to proxy to via NPM, but attempts to access it result in being redirected to with a NET::ERR_CERT_AUTHORITY_INVALID error mentioning a CloudFlare Origin Certificate.
Network Configuration:

My Omada controller has NAT rules set up as follows:
NPM ports 2053 and 8880 are forwarded to and, respectively.
Virtualmin ports 443 (HTTPS), 80 (HTTP), 53 (DNS), and 10000 (Webmin) are forwarded to their respective ports on

Despite correct DNS settings and NAT rules, accessing redirects me to, and the browser shows an SSL error due to the CloudFlare Origin Certificate, which should not be the case since is not using Cloudflare directly.
Possible Cause:

I suspect there might be a misconfiguration in NPM or a networking issue, possibly related to how NPM is set up in bridge mode while Virtualmin is on the host network.
I’ve double-checked my configurations but can’t seem to pinpoint the exact cause of the issue. I’m looking for insights or suggestions on how to resolve the redirection and SSL certificate problem for Has anyone experienced something similar or have any advice on troubleshooting these kinds of issues?

Thank you in advance for any help you can provide!

might not be related at all — how did you come to choose port 11000? I thought that was the default port for Usermin – do you have Usermin installed, configured and running?

Yes, virtualmin is installed and running. 10000 is the default port of virtualmin. 11000 is used by nextcloud, but added on NPM which is 80 and 443.

so sorry, I was WRONG. Usermin uses port 20000 !!

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