How to connect official wordpress docker-container via https

Dear all...

I've a problem to connect to my wordpress page via my duckdns domain (https).
On my local network I can connect to my wordpress page. When I switch the url iin wordpress to my duckdns domain (https) I can not connect anymore.
I'm already running nextcloud via letsencrypt and duckdns. That works like charm. I connected the official docker wordpress container to a specified docker network in which nextcloud and letsencrypt are already in. The wordpress container can only exposes port 80, could that be the problem? Could somebody give m some advice, how to get it work?

Many thanks in advanced for any suggestions.

Hello everybody...

running mariadb, duckdns, letsencrypt and wordpress with docker. On my local network everything works fine. With my duckdns domain it doesn't work. I did some research, but still no success.
I changed my wordpress.subdomain.conf (nginx letsencrypt) and my wp-config.php.

server {
listen 443 ssl;
listen [::]:443 ssl;
server_name example-blog.*;
include /config/nginx/ssl.conf;
client_max_body_size 0;
location / {
include /config/nginx/proxy.conf;
resolver 127.0.0.11 valid=30s;
set $upstream_wordpress wordpress;
proxy_max_temp_file_size 2048m;
proxy_pass https://xxx.xxx.xxx.xx:8080;
}
}

In wp-config.php I added the following line.

...


define('FORCE_SSL_ADMIN', true);
if ($_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https')
       $_SERVER['HTTPS']='on';


...

Tried it also with these lines from the info-page of docker official images wordpress.

...


define('FORCE_SSL_ADMIN', true);
// in some setups HTTP_X_FORWARDED_PROTO might contain 
// a comma-separated list e.g. http,https
// so check for https existence
if (strpos($_SERVER['HTTP_X_FORWARDED_PROTO'], 'https') !== false)
$_SERVER['HTTPS']='on';


...

On local side everything works. Via my duckdns domain no chance. I'm unable to connect. When I try to reach my site via https:\\domain.duckdns.org it's going to try port 8080. But this port isn't open and it shouldn't go throw this.
Anybody any solution?
Many thanks in advanced...

Thanks for the input Morlan.

I changed in the wordpress.subdomain.conf the proxy_pass and restarted letsencrypt.
Then I had my OMV login screen on https://example-blog.yourdomain.duckdns.org.
That's also good. My goal was only to get my blog on that domain.

My wordpress docker forwards port 8080 -> 80. So that's why I put 8080 to proxy_pass.
The configs are now looking like that.

server {
    listen 443 ssl;
    listen [::]:443 ssl;


    server_name mydomain.*;


    include /config/nginx/ssl.conf;


    client_max_body_size 0;


    location / {
        include /config/nginx/proxy.conf;
        resolver 127.0.0.11 valid=30s;
        set $upstream_wordpress wordpress;
        proxy_max_temp_file_size 2048m;
        proxy_pass http://xxx.xxx.xxx.xx:8080;
    }
}

...


define('FORCE_SSL_ADMIN', true);
if ($_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https')
       $_SERVER['HTTPS']='on';


...

I still can only connect to the blog on my local network.

I'm also expecting that the problem is somewhere in the wordpress configuration.

Using the official wordpress docker (Docker official images).
https://hub.docker.com/_/wordpress

On the official wordpress docker info page is a link how to use wordpress docker with a reverse proxy.
Following lines should be added to wp-config.php.

...


define('FORCE_SSL_ADMIN', true);
// in some setups HTTP_X_FORWARDED_PROTO might contain 
// a comma-separated list e.g. http,https
// so check for https existence
if (strpos($_SERVER['HTTP_X_FORWARDED_PROTO'], 'https') !== false)
$_SERVER['HTTPS']='on';


...

When I try to connect to my blog page firefox shows:

The page isn’t redirecting properly

An error occurred during a connection to mydomain.duckdns.org.

  This problem can sometimes be caused by disabling or refusing to accept cookie

I also looked in the wordpress database (wp_options) for siteurl (http://xxx.xxx.xxx.xx:8080) and home (https://mydomain.duckdns.org).
That's the actual state and no connection local and via mydomain. When I set both (siteurl and home) to http://xxx.xxx.xxx.xx:8080 I can reach my page on local network. I also tried both (siteurl and home) to https://mydomain.duckdns.org same like actual (first mentioned) database entry's.