I configured External Storage app for some local folder, and configured the Backup app to use it.
But when I try to do a manual backup (because, of course, automated one never worked), I got this error :
`sudo -u www-data php occ backup:point:create -vvv
maintenance mode: on
initialization of the AppData
maintenance mode: off
In ExternalFolderService.php line 354:
The destination folder exists and the permissions are correct. It is correctly selected in the Backup app.
What can I do ?