Nextcloud WebDAV only Temp Fileupload

i test Rocket Chat actually. I configure Nextcloud 18 WebDAV as Administrator, which is accessible from Windows10 Client. If a user uploads a file i got http error code 404 and on nextcloud i got an Tempfile with zero file size. NC Log shows: “Sabre\DAV\Exception\NotFound: File with name /RocketChatFiles/9cujJ7DXXKZqKkXWY could not be located”

Any idea?

Hi, can anyone help?