Sync issue Android / Raspberry / Nextcloud (or syncthing)

Operating system

Android

Joplin version

3.0.8

Desktop version info

Desktop version of Joplin: 3.1.20 (Ubuntu)
Android version of Joplin 3.0.8
Nextcloud (Docker) on raspberry pi 4: 30.0.1

Sync target

Nextcloud

What issue do you have?

Hi,
previously I was using SyncThing to sync the joplin files between the devices (2 Androids, Raspberry4, Ubuntu). But the Joplin app on my OnePlus 8T had an issue that blocked it. So for that time I downgraded to joplin 2.5.5.apk. All went well - as far as I could tell. But as time passes and my wife had no issue with her newer Joplin verision (Fairphone 5 with Android 14 I think), I wanted to finally upgrade to latest Joplin app. That was not working well, as the app told it is not able to access the files on my Android (I can retry and see the error message). So I switched to nextcloud instead to have a mitigation. There I used WebDav now. Copied the files to nextcloud drive, configured on Ubuntu and Android the access. Seems to work fine for desktop, except this open error:

"Abgeschlossen: 01/11/2024 11:31 (42s)
Letzte Fehlermeldung: Error: PROPFIND locks/: Der Server konnte die Anfrage nicht fertig stellen. Sollte dies erneut auftreten, sende bitte die nachfolgenden technischen Einzelheiten an deinen Server-Administrator. Weitere Details können im Server-Protokoll gefunden werden. (Exception Interner Serverfehler) (404): <?xml version="1.0" encoding="utf-8"?> <d:error xmlns:d="DAV:" xmlns:s="sabre/dav"> <s:exception>Interner Serverfehler</s:exception> <s:message> Der Server konnte die Anfrage nicht"

Seemed also rather slow for only 60MB (1000files). Maybe Raspberry is the bottle neck?

On Android it is not working at all. According to Joplin check it is fine, but no notes are coming. Error (shorted):
"Last error: PropFIND locks/: Server could not finish the request.Check with admin." (404)

Can you suggest which way to follow up? SyncThing or nextcloud and how to resolve the issues? I donated yesterday also to get this nice project running.
Help is appreciated - let me know which further infos you would need. Thx

P.S.: I also upgraded after first fail to SyncThing Fork as the original app was not existing anymore.