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Getting help
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- Official documentation (searchable and regularly updated)
- How to topics and FAQs
- Forum search
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Some or all of the below information will be requested if it isn’t supplied; for fastest response please provide as much as you can. 
The Basics
- Nextcloud Server version (e.g., 29.x.x):
- 34.0.4 (All in One)
- Operating system and version (e.g., Ubuntu 24.04):
- “Linux raspberrypi 6.12.109+rpt-rpi-2712 #1 SMP PREEMPT Debian 1:6.12.109-1+rpt1 (2026-09-11) aarch64 GNU/Linux”
- Web server and version (e.g, Apache 2.4.25):
AIO
- Reverse proxy and version _(e.g. nginx 1.27.2)
AIO
- PHP version (e.g, 8.3):
AIO
- Is this the first time you’ve seen this error? (Yes / No):
Yes
- When did this problem seem to first start?
Today
- Installation method (e.g. AlO, NCP, Bare Metal/Archive, etc.)
AIO
- Are you using CloudfIare, mod_security, or similar? (Yes / No)
No
Summary of the issue you are facing:
Upgrade of PreviewGenerator makes the webserver go “503” and stay offline.
Steps to replicate it (hint: details matter!):
-
Log in as admin
-
Select Apps from the menu
-
Click on “Updates”, since there is one.
-
See that the app that needs to be update is Preview Generator
-
Click “Upgrade to 5.15.0” from 5.14.0
-
Nextcloud System becomes unresponsive: other logged in users also only get 503 errors.
To get to the AIO page, I need to stop the apache docker container. Simply “starting” it after that does not help. If I go to the AIO interface and shut down all containers and then start them again the system works again, but the PreviewGenerator has not been upgraded.
I just upgraded 2 other apps too (including Mail), they went fine.
Log entries
Nextcloud
Please provide the log entries from your Nextcloud log that are generated during the time of problem (via the Copy raw option from Administration settings->Logging screen or from your nextcloud.log located in your data directory). Feel free to use a pastebin/gist service if necessary.
I've not seen anything in the log screen that I can identify from this time.
Web Browser
If the problem is related to the Web interface, open your browser inspector Console and Network tabs while refreshing (reloading) and reproducing the problem. Provide any relevant output/errors here that appear.
PASTE
Web server / Reverse Proxy
The output of your Apache/nginx/system log in /var/log/____:
PASTE HERE
Configuration
Nextcloud
The output of occ config:list system or similar is best, but, if not possible, the contents of your config.php file from /path/to/nextcloud is fine (make sure to remove any identifiable information!):
{ "system": { "one-click-instance": true, "one-click-instance.user-limit": 100, "memcache.local": "\\OC\\Memcache\\APCu", "apps_paths": [ { "path": "\/var\/www\/html\/apps", "url": "\/apps", "writable": false }, { "path": "\/var\/www\/html\/custom_apps", "url": "\/custom_apps", "writable": true } ], "check_data_directory_permissions": false, "memcache.distributed": "\\OC\\Memcache\\Redis", "memcache.locking": "\\OC\\Memcache\\Redis", "redis": { "host": "***REMOVED SENSITIVE VALUE***", "password": "***REMOVED SENSITIVE VALUE***", "port": 6379, "timeout": 3, "read_timeout": 10 }, "overwritehost": "nextcloud.hooft.net", "overwriteprotocol": "https", "passwordsalt": "***REMOVED SENSITIVE VALUE***", "secret": "***REMOVED SENSITIVE VALUE***", "trusted_domains": [ "localhost", "nextcloud.hooft.net" ], "datadirectory": "***REMOVED SENSITIVE VALUE***", "dbtype": "pgsql", "version": "34.0.4.1", "overwrite.cli.url": "https:\/\/nextcloud.hooft.net\/", "dbname": "***REMOVED SENSITIVE VALUE***", "dbhost": "***REMOVED SENSITIVE VALUE***", "dbport": "", "dbtableprefix": "oc_", "dbuser": "***REMOVED SENSITIVE VALUE***", "dbpassword": "***REMOVED SENSITIVE VALUE***", "installed": true, "instanceid": "***REMOVED SENSITIVE VALUE***", "maintenance": false, "loglevel": 2, "log_type": "file", "logfile": "\/var\/www\/html\/data\/nextcloud.log", "log_rotate_size": 10485760, "log.condition": { "apps": [ "admin_audit" ] }, "preview_max_x": 2048, "preview_max_y": 2048, "jpeg_quality": 60, "enabledPreviewProviders": { "0": "OC\\Preview\\Imaginary", "1": "OC\\Preview\\OpenDocument", "2": "OC\\Preview\\Movie", "3": "OC\\Preview\\Krita", "4": "OC\\Preview\\ImaginaryPDF", "5": "OC\\Preview\\ImaginaryPDF", "6": "OC\\Preview\\HEIC", "7": "OC\\Preview\\Image", "8": "OC\\Preview\\TIFF", "9": "OC\\Preview\\ImaginaryPDF", "10": "OC\\Preview\\ImaginaryPDF", "23": "OC\\Preview\\ImaginaryPDF", "24": "OCA\\Eurooffice\\Preview" }, "enable_previews": true, "upgrade.disable-web": true, "mail_smtpmode": "smtp", "trashbin_retention_obligation": "auto, 30", "versions_retention_obligation": "auto, 30", "activity_expire_days": 30, "simpleSignUpLink.shown": false, "share_folder": "\/Shared", "one-click-instance.link": "https:\/\/nextcloud.com\/all-in-one\/", "upgrade.cli-upgrade-link": "https:\/\/github.com\/nextcloud\/all-in-one\/discussions\/2726", "updatedirectory": "\/nc-updater", "maintenance_window_start": 100, "allow_local_remote_servers": true, "davstorage.request_timeout": 3600, "documentation_url.server_logs": "https:\/\/github.com\/nextcloud\/all-in-one\/discussions\/5425", "htaccess.RewriteBase": "\/", "dbpersistent": false, "auth.bruteforce.protection.enabled": true, "ratelimit.protection.enabled": true, "files_external_allow_create_new_local": false, "trusted_proxies": "***REMOVED SENSITIVE VALUE***", "preview_imaginary_url": "***REMOVED SENSITIVE VALUE***", "preview_imaginary_key": "***REMOVED SENSITIVE VALUE***", "mail_smtpauth": 1, "mail_sendmailmode": "smtp", "mail_smtpsecure": "ssl", "mail_from_address": "***REMOVED SENSITIVE VALUE***", "mail_domain": "***REMOVED SENSITIVE VALUE***", "mail_smtphost": "***REMOVED SENSITIVE VALUE***", "mail_smtpport": "465", "mail_smtpname": "***REMOVED SENSITIVE VALUE***", "mail_smtppassword": "***REMOVED SENSITIVE VALUE***", "default_phone_region": "NL", "updatechecker": false, "memories.db.triggers.fcu": true, "memories.exiftool": "\/var\/www\/html\/custom_apps\/memories\/bin-ext\/exiftool-aarch64-musl", "memories.vod.path": "\/var\/www\/html\/custom_apps\/memories\/bin-ext\/go-vod-aarch64", "memories.vod.ffmpeg": "\/usr\/bin\/ffmpeg", "memories.vod.ffprobe": "\/usr\/bin\/ffprobe", "memories.gis_type": 2, "serverid": 445, "log_type_audit": "file", "logfile_audit": "\/var\/www\/html\/data\/audit.log", "update_channel": "stable", "eurooffice": { "editors_check_interval": 0, "jwt_secret": "***REMOVED SENSITIVE VALUE***", "jwt_header": "AuthorizationJwt" }, "DOMAIN": "nextcloud.hooft.net", "AIO_VERSION": "v14.1.1" }}
Apps
The output of occ app:list (if possible).
Enabled:
- activity: 7.0.0
- admin_audit: 1.24.0
- appstore: 1.0.0
- assistant: 3.5.0
- bruteforcesettings: 7.0.0
- calendar: 6.6.1
- circles: 34.0.0
- cloud_federation_api: 1.18.0
- comments: 1.24.0
- contacts: 8.9.0
- contactsinteraction: 1.15.0
- cookbook: 0.11.10
- dashboard: 7.14.0
- dav: 1.40.0
- deck: 1.18.5
- eurooffice: 11.0.5
- federatedfilesharing: 1.24.0
- federation: 1.24.0
- files: 2.6.0
- files_downloadlimit: 5.2.0
- files_lock: 34.0.1
- files_pdfviewer: 7.0.0
- files_reminders: 1.7.0
- files_sharing: 1.26.0
- files_trashbin: 1.24.0
- files_versions: 1.27.0
- firstrunwizard: 7.0.0-dev.0
- integration_openai: 4.5.2
- logreader: 7.0.0
- lookup_server_connector: 1.22.0
- mail: 5.12.1
- memories: 9.0.1
- music: 3.2.1
- news: 28.7.0
- nextcloud-aio: 0.9.0
- nextcloud_announcements: 6.0.0
- notes: 6.1.0
- notifications: 7.0.0-dev.1
- notify_push: 1.4.1
- oauth2: 1.22.0
- office: 1.0.0
- password_policy: 6.0.0-dev.0
- passwords: 2026.9.20
- photos: 7.0.0
- previewgenerator: 5.14.0
- privacy: 6.0.0-dev.1
- profile: 1.3.0
- provisioning_api: 1.24.0
- recognize: 12.0.2
- recommendations: 7.0.0
- related_resources: 5.0.0-dev.0
- richdocumentscode_arm64: 26.4.303
- serverinfo: 6.0.0
- settings: 1.17.0
- sharebymail: 1.24.0
- spreed: 24.0.5
- support: 6.0.0
- survey_client: 6.0.0-dev.0
- systemtags: 1.24.0
- tables: 2.3.1
- tasks: 0.18.1
- text: 8.0.0
- theming: 2.9.0
- twofactor_backupcodes: 1.23.0
- twofactor_totp: 16.0.0
- updatenotification: 1.24.0
- user_status: 1.14.0
- viewer: 7.0.0-dev.0
- weather_status: 1.14.0
- webhook_listeners: 1.6.0
- whiteboard: 2.0.0
- workflowengine: 2.16.0
Disabled:
- app_api: 34.0.0 (installed 4.0.5)
- encryption: 2.22.0
- files_external: 1.26.0
- suspicious_login: 12.0.0-dev.0
- twofactor_nextcloud_notification: 8.0.0
- user_ldap: 1.25.0