Hey I solved It by adding in my nextcloud configuration this in /etc/apache2/apache2.conf:
ServerName my.domain.org
Also in /var/www/nextcloud/config/config.php
'trusted_domains' =>
array (
0 => '192.168.1.13:8282',
1 => 'my.domain.org',
),
'trusted_proxies' =>
array (
0 => '172.28.0.0/16',
),
and in my traefik docker-compose.yml:
command:
- "--providers.docker.network=traefik"