I use MadieWiki 1.35.2 on Ubuntu. Everything works fine including image upload.
Now I allowed also PDF upload via
$wgFileExtensions = [ 'png', 'gif', 'jpg', 'jpeg', 'webp', 'pdf' ];
Unfortuately it does not work. I get the error
Fehler beim Hochladen
Das Verzeichnis „mwstore://local-backend/local-public/5/5f“ konnte nicht angelegt werden.
The permissions seems to be Ok since I can actually upload images.
Enabling the "PdfHandler" extension (of course with all needed packages installed) makes no difference. I get the same error.
Any clue about the reason of this issue i.e. why does especially an upload of a PDF gives this error?