Apps are unable to access files

[sebii]

Installation

Nextcloud version : 30.0.0.14
Operating system and version: Debian GNU/Linux 12 (bookworm)
Apache version: 2
PHP version: 8.2.24

docker-compose.yml

volumes:
  nextcloud:
  db:

services:
  db:
    image: mariadb:10.6
    restart: always
    command: --transaction-isolation=READ-COMMITTED --log-bin=binlog --binlog-format=ROW
    volumes:
      - db:/var/lib/mysql
    environment:
      - MYSQL_ROOT_PASSWORD=...
      - MYSQL_PASSWORD=...
      - MYSQL_DATABASE=nextcloud
      - MYSQL_USER=nextcloud

  app:
    image: nextcloud
    restart: always
    tmpfs:
      - /tmp:exec
    ports:
      - 8080:80
    links:
      - db
    volumes:
      - ./main:/var/www/html
      - db:/var/lib/mysql
      - ./main:/var/www/html
      - ./apps:/var/www/html/custom_apps
      - ./config:/var/www/html/config
      - ./data:/var/www/html/data
    environment:
      - MYSQL_PASSWORD=...
      - MYSQL_DATABASE=nextcloud
      - MYSQL_USER=nextcloud
      - MYSQL_HOST=db

Issue

I am having an issue when apps try to access local files. For example using the popular Memories-app: When adding a path in its menu, I see my directories and their respective size/last modified. But when clicking on them there are no files to be found. Also the app itself shows no images. Some other apps like mediadc cause server errors.

Altought

To reproduce this issue, install nextcloud with given docker-compose.yml, install any app and try to access local files.

Logs/Config

Admin > Logging

Multiple times:

RuntimeException image not found: image:apps/whiteboard.svg webroot: serverroot:/var/www/html

config.php

$CONFIG = array (
  'htaccess.RewriteBase' => '/',
  'memcache.local' => '\\OC\\Memcache\\APCu',
  'apps_paths' =>
  array (
    0 =>
    array (
      'path' => '/var/www/html/apps',
      'url' => '/apps',
      'writable' => false,
    ),
    1 =>
    array (
      'path' => '/var/www/html/custom_apps',
      'url' => '/custom_apps',
      'writable' => true,
    ),
  ),
  'upgrade.disable-web' => true,
  'instanceid' => 'ocbkcv2nooa1',
  'passwordsalt' => '...',
  'secret' => '...',
  'trusted_domains' =>
  array (
    0 => '...:8080',
  ),
  'datadirectory' => '/var/www/html/data',
  'dbtype' => 'mysql',
  'version' => '30.0.0.14',
  'overwrite.cli.url' => 'http://...:8080',
  'dbname' => 'nextcloud',
  'dbhost' => 'db',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'mysql.utf8mb4' => true,
  'dbuser' => 'nextcloud',
  'dbpassword' => '...',
  'installed' => true,
  'memories.exiftool' => '/var/www/html/custom_apps/memories/bin-ext/exiftool-aarch64-glibc',
  'memories.vod.path' => '/var/www/html/custom_apps/memories/bin-ext/go-vod-aarch64',
  'memories.index.path' => '/Photos',
  'loglevel' => 2,
  'maintenance' => false,
);

Unfortunately, I am unable to print /var/log/apache2/error.log using cat.

I suspect, I have a misconfiguration in docker-compose.yml, but I reread everything I found at least twice, so I think I must have overlooked something.

Thank you for any help!