Nexcloud 14 User can't share files

after upgrading from Nextcloud 13 to 14 our users can’t share any files.
When I want to share a file the window on the right side opens with the filename and the circle ist rotating but the other fields and checkboxed doesn’t apear.
When I do the same as Admin I don’t have any problems.
When I want to open the uploaded file I get an error “Not Found”. I checked the filesystem and I can find the file in my userfolder but I can see that my old files have the permission -rw-r-----. The new files have -rw-r–r--.
Any ideas?

Nextcloud version 14.0.0
Operating system and version Raspberry Pi Debian Strech
Nginx version 1.10.3
PHP version 7.0.30

I found this error in my logfile:
webdav Sabre\DAV\Exception\NotFound: File with name remote.php/dav/files/Username/filename.gif could not be located

  1. /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/CorePlugin.php - line 81:OCA\DAV\Connector\Sabre\ObjectTree->getNodeForPath(“remote.php/ … f”)
  2. Sabre\DAV\CorePlugin->httpGet(Sabre\HTTP\R … "}, Sabre\HTTP\Response {})
  3. /var/www/nextcloud/3rdparty/sabre/event/lib/EventEmitterTrait.php - line 105:call_user_func_array([ Sabre\DAV\ … "], [ Sabre\HTTP … }])
  4. /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php - line 479:Sabre\Event\EventEmitter->emit(“method:GET”, [ Sabre\HTTP … }])
  5. /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php - line 254:Sabre\DAV\Server->invokeMethod(Sabre\HTTP\R … "}, Sabre\HTTP\Response {})
  6. /var/www/nextcloud/apps/dav/appinfo/v1/webdav.php - line 80:Sabre\DAV\Server->exec()
  7. /var/www/nextcloud/remote.php - line 163:require_once("/var/www/ne … p")

Solved with Nextcloud 14.0.1