Possible data loss after Document Server connection failure

[apfelpfluecker]

Steps to reproduce

Unfortunately I cannot provide reliable reproduction steps because the issue was only discovered after the fact.

The observed sequence was:

1. Open a document in ONLYOFFICE through Nextcloud.
2. Edit the document over a period of several weeks.
3. Regularly close and reopen the document.
4. Receive a notification email from Nextcloud stating that the ONLYOFFICE Document Server is unavailable.
5. Discover that the document stored in Nextcloud is only at the state it had approximately four weeks earlier.

Expected behaviour

Document changes should be saved back to Nextcloud when the document is closed.

If saving fails, users should receive a clear error message and there should be no risk of silently losing weeks of edits.

Actual behaviour

The document was edited extensively over several weeks and appeared to work normally.

After receiving the "ONLYOFFICE Document Server is not available" notification, I discovered that:

• The document in Nextcloud only contains content from approximately four weeks ago.
• The Nextcloud version history also only contains versions up to that point.
• A Nextcloud backup taken before the notification email also contains only the old version.

This raises the concern that document changes may have existed only on the Document Server and were never written back to Nextcloud.

My main question is whether there is any possibility to recover such data from the Community Document Server (temporary files, caches, database entries, Docker volumes, etc.).

Server configuration

Web server: Unknown (managed Nextcloud by Hetzner), probably: Linux 6.8.0-106-generic x86_64

Database: mysql, 10.11.18

PHP version: 8.3.30

Nextcloud version: Current Hetzner-managed installation (can provide exact version if needed)

List of activated apps

Contacts
ONLYOFFICE
Activity
Brute-force-settings
Calendar
Client Push
Collaborative Tag
Comments
Community Document Server
Contacts Interaction
Dashboard
Deck
Deleted Files
Federation
File Reminders
File Sharing
Files download limit
First run wizard
Keeweb
Monitoring
Nextcloud Announcements
Nextcloud webhooks support
Notes
Notifications
PDF viewer
Password Policy
Photos
Polls
Pride Flags
Privacy
Quota warning
Recommendations
Related resources
Share by mail
Support
Talk
Tasks
Team Folders
Teams
Text
Two-factor-authentification…
Update notification
User status
Versions
Weather status

Nextcloud configuration

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Browser

Browser name: Firefox (Flatpak)

Browser version: 151.0.3 (64-Bit)

Operating system: Linux, Zorin OS 18.1 Education

Browser log

No browser logs available because the issue was only noticed retrospectively.

The only notification received was:

"ONLYOFFICE Document Server is not available. This is an email message to notify you that the connection with the ONLYOFFICE Document Server has been lost. Please check the connection settings."