Links keep dissapearing

Nextcloud version (eg, 12.0.2): 18.0.0
Operating system and version (eg, Ubuntu 17.04): Centos
Apache or nginx version (eg, Apache 2.4.25): DOCKER IMAGE
PHP version (eg, 7.1): DOCKER IMAGE

docker-compose.yml

version: '3'

services:
  mysql:
    image: mariadb:10.4
    restart: unless-stopped
    env_file:
      - db.env
    networks:
      - default
    volumes:
      - "./_data/mysql:/var/lib/mysql"
    command: --transaction-isolation=READ-COMMITTED --binlog-format=ROW --log-bin=/var/log/mysql/mariadb-bin

  redis:
    image: redis:5.0-alpine
    restart: unless-stopped
    networks:
      - default
    volumes:
      - "./_data/redis:/data"

  elasticsearch:
    image: docker.elastic.co/elasticsearch/elasticsearch:7.3.2
    restart: always
    environment:
      - node.name=es01
      - discovery.type=single-node
      - "ES_JAVA_OPTS=-Xms512m -Xmx512m"
    ulimits:
      memlock:
        soft: -1
        hard: -1
    volumes:
      - /etc/localtime:/etc/localtime:ro
      - /etc/timezone:/etc/timezone:ro
      - ./_data/elasticsearch/data:/usr/share/elasticsearch/data
      - ./_data/elasticsearch/plugins:/usr/share/elasticsearch/plugins
    networks:
      - default

  nextcloud:
    image: nextcloud:18-apache
    restart: unless-stopped
    depends_on:
      - mysql
      - redis
    env_file:
      - db.env
    environment:
      MYSQL_HOST: mysql
      REDIS_HOST: redis
      SMTP_HOST: 172.17.0.1
    labels:
      - "traefik.enable=true"
      - "traefik.frontend.rule=Host:data.xx.de,data.xx.com"
      - "traefik.frontend.redirect.permanent=true"
      - "traefik.frontend.redirect.regex=https://(.*)/.well-known/(card|cal)dav"
      - "traefik.frontend.headers.STSSeconds=15552000"
      - "traefik.frontend.headers.STSIncludeSubdomains=true"
      - "traefik.frontend.headers.STSPreload=true"
      - "traefik.http.routers.nextcloud-https.tls=true"
      - "traefik.frontend.redirect.replacement=https://$$1/remote.php/dav/"
    networks:
      - default
      - web
    volumes:
      - "./nextcloud:/var/www/html"
      - "/mnt/zraid/data/nc_data:/var/www/html/data"
      - "/mnt/zraid/data/Audio:/mnt/Audio"
      - "/mnt/zraid/data/YannickLanger:/mnt/YannickLanger"
      - "/mnt/zraid/data/ButtonBeFactory:/mnt/ButtonBeFactory"
      - "/mnt/zraid/data/SoulFulFactory:/mnt/SoulFulFactory"
      - "/mnt/zraid/data/SISKASElement:/mnt/SISKASElement" 
      - "/mnt/zraid/data/Final_Cut:/mnt/FinalCut"
      - "/mnt/zraid/data/Scan:/mnt/Scan"
      - /opt/nextcloud/memory-limit.ini:/usr/local/etc/php/conf.d/memory-limit.ini:ro

  cron:
    image: nextcloud:18-apache
    restart: unless-stopped
    depends_on:
      - mysql
      - redis
    volumes:
      - "./nextcloud:/var/www/html"
      - "/mnt/zraid/data/nc_data:/var/www/html/data"

    entrypoint: /cron.sh

#  onlyoffice-document-server:
#    container_name: onlyoffice-document-server
#    image: onlyoffice/documentserver:latest
#    stdin_open: true
#    tty: true
#    restart: always
#    labels:
#          - "traefik.enable=true"
#          - "traefik.frontend.rule=Host:doc.ylfl.de,doc.soulfulfactory.com"
#          - "traefik.frontend.redirect.permanent=true"
#          - "traefik.frontend.redirect.regex=https://(.*)/.well-known/(card|cal)dav"
#          - "traefik.frontend.redirect.replacement=https://$$1/remote.php/dav/"
#    volumes:
#      - /mnt/zraid/data/onlyoffice/document_data:/var/www/onlyoffice/Data
#      - /mnt/zraid/data/onlyoffice/document_log:/var/log/onlyoffice
#    networks:
#      - default
#      - web


networks:
  web:
    external: true

The issue you are facing:
I added external Files to my Nextcloud Docker Setup and shared links keep dissapearing.

Is this the first time you’ve seen this error? (Y/N): N

Steps to replicate it:

  1. Add Shared Files as Volume to your Docker-Compose.yml
  2. Scan all and Share the file
  3. External users cant Access it and keep getting “A File Not Found Error”

The output of your Nextcloud log in Admin > Logging:

[webdav] Fatal: OCP\Files\NotFoundException: /yannicklanger/files/YannickLanger/03_Noten/05_Git/94.000 Tabs/48000tab/Pop_Rock/Every_Little_Thing at <<closure>>

 0. /var/www/html/lib/private/Files/Node/Folder.php line 137
    OC\Files\Node\Root->get("/yannicklanger/ ... g")
 1. /var/www/html/apps/dav/lib/Connector/Sabre/SharesPlugin.php line 157
    OC\Files\Node\Folder->get("/YannickLanger/ ... g")
 2. /var/www/html/apps/dav/lib/Connector/Sabre/SharesPlugin.php line 200
    OCA\DAV\Connector\Sabre\SharesPlugin->getShares(OCA\DAV\Connector\Sabre\Directory {})
 3. /var/www/html/3rdparty/sabre/dav/lib/DAV/PropFind.php line 98
    OCA\DAV\Connector\Sabre\SharesPlugin->OCA\DAV\Connector\Sabre\{closure}("*** sensitive parameters replaced ***")
 4. /var/www/html/apps/dav/lib/Connector/Sabre/SharesPlugin.php line 207
    Sabre\DAV\PropFind->handle("{http://owncloud.org/ns}share-types", Closure {})
 5. <<closure>>
    OCA\DAV\Connector\Sabre\SharesPlugin->handleGetProperties(Sabre\DAV\PropFind {}, OCA\DAV\Connector\Sabre\Directory {})
 6. /var/www/html/3rdparty/sabre/event/lib/EventEmitterTrait.php line 105
    call_user_func_array([OCA\DAV\Connect ... "], [Sabre\DAV\PropF ... }])
 7. /var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php line 1059
    Sabre\Event\EventEmitter->emit("propFind", [Sabre\DAV\PropF ... }])
 8. /var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php line 981
    Sabre\DAV\Server->getPropertiesByNode(Sabre\DAV\PropFind {}, OCA\DAV\Connector\Sabre\Directory {})
 9. /var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php line 1666
    Sabre\DAV\Server->getPropertiesIteratorForPath("files/yannickla ... g", ["{DAV:}resource ... "], 1)
10. /var/www/html/3rdparty/sabre/dav/lib/DAV/CorePlugin.php line 355
    Sabre\DAV\Server->generateMultiStatus(Generator {}, false)
11. <<closure>>
    Sabre\DAV\CorePlugin->httpPropFind(Sabre\HTTP\Reque ... "}, Sabre\HTTP\Response {})
12. /var/www/html/3rdparty/sabre/event/lib/EventEmitterTrait.php line 105
    call_user_func_array([Sabre\DAV\CorePlugin {},"httpPropFind"], [Sabre\HTTP\Requ ... }])
13. /var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php line 479
    Sabre\Event\EventEmitter->emit("method:PROPFIND", [Sabre\HTTP\Requ ... }])
14. /var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php line 254
    Sabre\DAV\Server->invokeMethod(Sabre\HTTP\Reque ... "}, Sabre\HTTP\Response {})
15. /var/www/html/apps/dav/lib/Server.php line 319
    Sabre\DAV\Server->exec()
16. /var/www/html/apps/dav/appinfo/v2/remote.php line 35
    OCA\DAV\Server->exec()
17. /var/www/html/remote.php line 165
    require_once("/var/www/html/a ... p")

PROPFIND /remote.php/dav/files/yannicklanger/YannickLanger/03_Noten/05_Git/94.000%20Tabs/48000tab/Pop_Rock/Every_Little_Thing
from 172.18.0.3 by yannicklanger at 2020-02-14T14:40:17+00:00

The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):

<?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,
    ),
  ),
  'memcache.distributed' => '\\OC\\Memcache\\Redis',
  'memcache.locking' => '\\OC\\Memcache\\Redis',
  'redis' => 
  array (
    'host' => 'redis',
    'port' => 6379,
    'password' => false,
  ),
  'instanceid' => 'ocmac23wi1t3',
  'dbtype' => 'mysql',
  'version' => '18.0.0.10',
  'overwrite.cli.url' => 'http://data.xx.com',
  'overwriteprotocol' => 'https',
  'dbname' => 'nextcloud',
  'dbhost' => 'mysql',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'mysql.utf8mb4' => true,
  'dbuser' => 'xx',
  'dbpassword' => 'xx',
  'passwordsalt' => 'xx',
  'secret' => 'xx',
  'trusted_domains' => 
  array (
    0 => 'data.xx.com',
  ),
  'datadirectory' => '/var/www/html/data',
  'installed' => true,
  'maintenance' => false,
  'theme' => '',
  'loglevel' => 2,
  'mail_smtpmode' => 'smtp',
  'mail_smtphost' => 'xxx',
  'mail_sendmailmode' => 'smtp',
  'mail_smtpsecure' => 'ssl',
  'mail_from_address' => 'no-reply',
  'mail_domain' => 'xx.xx',
  'mail_smtpauthtype' => 'LOGIN',
  'mail_smtpauth' => 1,
  'mail_smtpport' => '465',
  'mail_smtpname' => 'xx',
  'mail_smtppassword' => 'xx/xx/xx',
  'data-fingerprint' => 'xxx',
  'app_install_overwrite' => 
  array (
    0 => 'contacts',
  ),
);