NPM-Official and browser SSL cert errors

Hi I'm having a problem with SSL certs, on Firefox I'm getting SSL_ERROR_INTERNAL_ERROR_ALERT (with Chrome it's a ERR_SSL_PROTOCOL_ERROR) when navigating to my proxy host. Below are the setup steps I followed along with the troubleshooting I did. Short of testing the SSL cert on a webserver to verify that it is intact (please let me know if I should attempt this), I'm out of ideas. Any help is greatly appreciated.

The setup steps I followed:

1. Setup a subdomain haos.mydomain.com to redirect to my top-level domain, mydomain.com

2. Verify that mydomain.com is currently pointed to my dynamic IP (via dynamic DNS).

3. Follow this tutorial to setup NPM-Official, which is basically:
   https://www.youtube.com/watch?v=nhacNUxVcy4

   1. Install NPM-Official container. Choose to have a fixed IP address.

   2. Forwarded ports 80 and 443 from my router to the NPM-Official IP address.

   3. Verify that I can access the NPM-Official welcome screen when navigating to http://myipaddress

   4. Setup mydomain.com and *.mydomain.com SSL Certs in the NPM webUI. I deviated from the tutorial by enabling DNS Challenge to allow wildcard cert generation.

   5. Create a Proxy Host. It's pointed to my HA OS virtual machine, so http and port 8123. It uses the *.mydomain.com SSL cert.

Now I should be able to type in haos.mydomain.com via http or https and see the HA OS interface. But instead, what I see with http is 502 bad gateway, and with https SSL_ERROR_INTERNAL_ERROR_ALERT on Firefox and with Chrome it's a ERR_SSL_PROTOCOL_ERROR.

Troubleshooting:

• nslookup says haos.mydomain.com is correctly pointed to my external IP address

• manually navigating to the HA OS IP address successfully shows me the HA web interface as expected

• NPM-Official log shows successful cert generation when I click on Renew:
  

[7/5/2025] [8:40:19 PM] [SSL ] ›  info
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Processing /etc/letsencrypt/renewal/npm-2.conf
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Renewing an existing certificate for *.mydomain.com and mydomain.com
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Congratulations, all renewals succeeded: /etc/letsencrypt/live/npm-2/fullchain.pem (success)
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[7/5/2025] [8:40:19 PM] [Global ] › ⬤ debug CMD: openssl x509 -in /etc/letsencrypt/live/npm-2/fullchain.pem -subject -noout
[7/5/2025] [8:40:19 PM] [Global ] › ⬤ debug CMD: openssl x509 -in /etc/letsencrypt/live/npm-2/fullchain.pem -issuer -noout
[7/5/2025] [8:40:19 PM] [Global ] › ⬤ debug CMD: openssl x509 -in /etc/letsencrypt/live/npm-2/fullchain.pem -dates -noout

Edited July 6, 2025Jul 6 by gusgus
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