Cannot export my own calendars to a file

Nextcloud version (eg, 20.0.5): Nextcloud AIO v4.0.1
PHP version (eg, 7.4): 8.0.26

The issue you are facing:

Hi all,

I am running Nextcloud AIO v4.0.1 on a VPS, remotely, and everything has been working well and solid for a while.

However, since the last update I have done to my installation, I am not able to export my own calendars anymore, using the export feature in the Calendar. Why is this happening? I have rebooted the instance several times, to no avail.

When I click on the export button, the screens goes blank and this is the link it points to:

Nothing happens.

The VPS doesn’t allow me to access the /var/www folder either, so I am not sure how to find it? Any tips are appreciated.

Is this the first time you’ve seen this error? (Y/N): Yes

Steps to replicate it:
Happens all the time.

The output of your Nextcloud log in Admin > Logging:

[index] Error: Exception: OCA\Calendar\Controller\SettingsController::setConfig(): Argument #2 ($value) must be of type string, null given, called in /var/www/html/lib/private/AppFramework/Http/Dispatcher.php on line 225 in file '/var/www/html/custom_apps/calendar/lib/Controller/SettingsController.php' line 71 at <<closure>>

0. /var/www/html/lib/private/AppFramework/App.php line 172
   OC\AppFramework\Http\Dispatcher->dispatch(OCA\Calendar\Con ... {}, "setConfig")
1. /var/www/html/lib/private/Route/Router.php line 298
   OC\AppFramework\App::main("OCA\\Calendar\\ ... r", "setConfig", OC\AppFramework\ ... {}, ["view","calendar.settings.setConfig"])
2. /var/www/html/lib/base.php line 1047
3. /var/www/html/index.php line 36

POST /index.php/apps/calendar/v1/config/view
from by admin at 2023-01-02T19:26:52+00:00

See Export calendars with 4.2.0 gives TypeError: Cannot read properties of null (reading 'getUTCFullYear') · Issue #4844 · nextcloud/calendar · GitHub