owncloud as docker an nginx proxy_pass and trusted domain

Question

I deployed a docker with owncloud. I'm using nginx on the host-server (vserver).

Here my nginx configuration:

server {
        server_name owncloud.mydomain.de;

        location / {
                proxy_pass http://localhost:8080;
                proxy_intercept_errors on;
                proxy_set_header Host $host;
                proxy_set_header X-Real-IP $remote_addr;
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_connect_timeout 150;
                proxy_send_timeout 100;
                proxy_read_timeout 100;
                proxy_buffers 4 32k;
                client_max_body_size 8m;
                client_body_buffer_size 128k;
        }

...

and on config.php of owncloud I try to set the paramater for trusted domains:

'trusted_domains' =>
  array (
    0 => 'localhost',
    1 => 'owncloud.mydomain.de',
  ),

Unfortunately it doesn't work and the result is from owncloud in browser:

"You are accessing the server through an untrusted domain"

What is wrong? Thank you for help.

"You are accessing the server through an untrusted domain" in Browser.