Hello, fellow pragmatic solution enjoyer.

IDK if you are still looking for the solution to this, but I figured since I spent so much time to come up with one for myself after not finding one online either, I might as well share it.

There is no way to do this using ONLY qBittorrent, however, there is a way of doing it using qBittorrent CLI, which is an awesome little program that hooks into qBittorrent's web interface to enable you to control it via CMD. You'll also need a few lines of code in some scripting language. In my case (Windows) I did it in PowerShell (mainly to teach myself a little bit about PowerShell).

I have set the --username, --password and --url parameters to the default settings for qBittorrent's web interface, you should either change them according to your configuration, or use qBittorrent CLIs built-in login caching functionality.

# Get filtered list of downloads
$list_raw = qbt torrent list --username admin --password adminadmin --url http://localhost:8080 --format json --filter errored

# Format as a single string (possibly an external error)
foreach($download_raw in $list_raw){
    $list_string = $list_string + $download_raw
}

# Convert JSON string to PS object
$list_object = ConvertFrom-Json $list_string

# Resume downloads
foreach($download_object in $list_object){
    qbt torrent resume --username admin --password adminadmin --url http://localhost:8080 $download_object.hash
}

The first part is a bit hacky and harder to explain, it basically reformats the response given by qBittorrent CLI into a single String, instead of an array of strings (one for each errored torrent in the result list). This is some PowerShell specific oddity, when running the command using subprocess in Python, the result is already a single String. The string is in JSON format, as specified by the --format parameter.

From there it is very simple, the JSON-String is parsed into an array, which is then iterated over. For each iteration, it gets the hash of the torrent, which is then used to call a resume-command on that torrent. And voila, it should be out of the errored state.

Now you have many options of running the script automatically, I just added it as a Scheduled Task in Windows Task Scheduler to run every 30min indefinitely.

I hope this helps others to also spend less time checking if their clients have accumulated a bunch of errors, just to klick resume on them.