This directory is not available [...] (Trashcan)

Nextcloud version: 21.0.5
OS: Raspbian
Apache version: 2.4.38
PHP version : 7.3.29-1

Issue: App "webdav" => Message "TypeError"
This is the first time I’ve had this bug

  1. I deleted files that were over 16GB in total
  2. The recycle bin could no longer be accessed and the following error was displayed: This directory is not available, please check the log files or contact the administrator.
  3. The files were saved all at once in a folder in the recycle bin (in /files_trashbin/files) (some hash name), even deleting this folder did not help. (I did that at FileZilla)

Output of Nextcloud log in Admin > Logging:


'datadirectory' => '/media/storage/data', <<< (on an external hard drive)