Bug: Images are not uploaded when the upload is interrupted

Steps to reproduce

The main way to reproduce is to interrupt the upload. This method was quiet reliable for me:

1. Enable Wifi only upload and disable Wifi
2. Take a photo and open the app -> the red 1 for a new image pops up
3. Close and reopen the app

Expected behaviour

The App should retry the upload ones connected to wifi

Actual behaviour

The 1 disappears and the image is never uploaded even when reconnected to Wifi.

Logs

There is also a error message in the logs:

Network completed upload file: https://nextcloudserver/remote.php/webdav/Photos/21-06-06 12-43-06 2874.jpg with error code -999 and error description Der Vorgang konnte nicht abgeschlossen werden. (NSURLErrorDomain-Fehler -999.)

Reasoning or why should it be changed/implemented?

This Problem is new. A few months ago the upload worked!

Environment data

iOS version: iOS 14.5.1

Nextcloud iOS app version: Nextcloud Coherence for iOS 3.4.2.0 @ 2021

Server operating system: Docker on Ubuntu

Web server: nginx

Database: mariadb

PHP version: 7.4.20

Nextcloud version: 20.0.10

Start by reproducing the interrupted upload with Wi-Fi-only uploads disabled, then reconnect to Wi-Fi and inspect the upload flow around the reported NSURLErrorDomain -999 log. Trace how the pending image is handled after the app is closed and reopened; done means the image remains pending and is retried and uploaded when Wi-Fi becomes available.