"Can you post the relevant part of your config_local.php (that what you have changed)?"
* BEWARE : it has to end with a /
*/
$config['calibre_directory'] = '/media/pi/MEDIA/calibre_ebooks/';
I can confirm it's the correct path:
pi@van:/var/www/html/ebooks $ cd /media/pi/MEDIA/calibre_ebooks/
pi@van:/media/pi/MEDIA/calibre_ebooks $ ls -l
total 14120
drwxrwsrwx 4 pi pi 4096 Aug 31 19:29 Aaron Anderson
drwxrwsrwx 70 pi pi 4096 Aug 31 19:29 Agatha Christie
...
-rwxrwxrwx 1 pi pi 11832320 Aug 31 19:23 metadata.db
-rwxrwxrwx 1 pi pi 14853 Aug 31 19:24 metadata_db_prefs_backup.json
...
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