V2: ⪅ versionName=4.5.4-ose reports HTTP 400 some months after adding the account, when synchronising, because it attempts to access a 404 NextCloud text/calendar file.

[RokeJulianLockhart]

Problem scope

• I'm sure that this is a DAVx⁵ problem.

App version

• I'm using the latest available DAVx⁵ version.

Android version and device/firmware type

1. The OS

   [ro.build.version.release]: [15]
   [ro.build.display.id]: [FP5.VT2E.C.059.20250908]

2. The Device

   [ro.product.brand]: [Fairphone]
   [ro.build.product]: [FP5]

Steps to reproduce

To reproduce it, merely synchronise:

screen-20250904-223334.mp4

Visiting the URI (https://wim.nl.tab.digital/remote.php/dav/calendars/rokejulianlockhart/3de72895-d345-4ac4-8eec-1418e857ba7e/47b29e62-1c12-497d-936f-55480815b63b.ics) in firefox-142.0-1.fc42, I see a 404 equivalent:

Actual result

(At least ⪅ versionCode=405040005) reports HTTP 400 ⪅ P6M subsequent to addition of the account, when accessing a text/calendar file stored in a NextCloud instance (version: 30.0.12.2)'s remote.php/dav/calendars.

A temporary solution appears to be removal, then re-addition, of the affected account from com.nextcloud.android.beta/com.owncloud.android.ui.activity.ManageAccountsActivity. ¹ However, it solely remediates it for ⪅ P6M, so I want to ascertain what the cause and solution are. ² Additionally, ascertaining whether that method continues to remediate this is difficult:

1. ...because it removes my ability to diagnose the fault until it recurs.

2. ...due to the quantity of accounts added:

   Details

   

Expected result

Because I have little reason to expect such an error, ³ I doubt that I should see one.

Further info

Diagnosis

davx5-debug.zip provides the error, alongside relevant diagnostic information, including my environment. Per the debug log, this might relate to issues/3333. It doesn't appear to reproduce as discussions/377#discussioncomment-6708873 does. Similarly, my environment differs to what discussions/912#discussion-6938458 describes.

By utilising android.stackexchange.com/questions/203868#comment356748_247052, I tracked:

Name: DAVx⁵
Package name: at.bitfire.davdroid
UID: 10219
Version: 4.5.4-ose
Target SDK: 36
Installed on: 04/24/24 19:22:22
Last update: 09/20/25 16:15:00
Traffic: 34.6 KB received — 22.1 KB sent
Connections: 5

...during which it reproduced. If the resultant .pcap is of use, I shall provide it. ⁴

Footnotes

1. discussions/43#discussioncomment-2803653 ↩

2. discussions/43#discussioncomment-14312040 ↩

3. nextcloud/calendar/issues/1508#issuecomment-3410869786 ↩

4. drive.google.com/drive/folders/1FZQZpzOMtnuJB2sHOi8j7wC-Oxoa5bFS ⁵ ↩

5. security.stackexchange.com/revisions/77092/1 ↩

[RokeJulianLockhart]

#event-20410322490

@rfc2822, why is this a discussion? (Did you read it?) I'd already posted a discussion years ago. ¹

Footnotes

1. discussions/43#discussioncomment-14702062 ↩

[RokeJulianLockhart]

I'm not sure how to debug this further - you can try to have a look into the webserver logs and maybe there is some more info about that...

@devvv4ever, unfortunately, I've no control over the server, and I doubt that support.tab.digital would much care, or be capable of diagnosing it.

But, as a workaround, try to find this task on the server and delete it. Also delete it in tasks.org on the Android device, and, then, run the sync again — hopefully without errors. If the sync succeeds, you need to re-add this task again.

If it does not work switch off “Inclusive Event, Task, and Document Storage” in the DAVx5 account, press sync (= will remove all tasks, events from the device — even ones that have not been synced to the server (!)), re-enable it and sync again. This will make a fresh sync of the state of the server for this calendar.

If we can't diagnose this further, I'll redo everything. I've been trying to keep everything as-is so that it could be diagnosed to prevent it recurring, but I understand if diagnosis in this case is too dependent upon access to the NC server that I don't control. Thanks.

[thomasfrobieter]

Would it be possible for DAVx5 to show a dialogue similar to the Nextcloud app if there is a file sync conflict? Something like 'The task ID x already exists'. A) Override on remote, B) Pull from remote, override local"?

I'm not sure if this is the responsibility of DAVx5 or Tasks.org, but it definitely shouldn't be the end user's responsibility!

[rom1dep]

If it does not work switch off "Inclusive Event, Task, and Document Storage" in the DAVx5 account,

@devvv4ever Hi! I can't find that anywhere, could you please indicate the steps to do that? Thanks!

[RokeJulianLockhart]

@rom1dep, that is what I named the task list that was affected, so all that they refer to is disabling the task list.

[rom1dep]

@RokeJulianLockhart ohhh! yeah, that's indeed a silly option name to be looking for ;-)

For the record, I'm bumping into this problem as well. I did an ICS export of the problematic list from nextcloud and restored it into a blank new task list (via korganizer). davx5 also had issues with the new list (while being fully functional in korganizer/nextcloud), so I deleted tasks one after the other until the new list was empty. And synced. And every now and then, task.org/davx5 is resurrecting some zombie tasks which no other client (nextcloud, korganizer) is seeing. I am not sure what else to do.