The Android App “FolderSync” stopped working when I upgraded my ownCloud to Version 7. FolderSync always showed “Bad Request” when testing the connection. ANd when I looked into the Apache log, the requests were closed with “400 Bad Request”. But I found the solution here (german page):

To get FolderSync working with ownCloud 7 you have to add a second line with the HTTPS port 443 to your config.php:

In ${OWNCLOUD_DIR}/config/config.php:

  'trusted_domains' =>
  array (
    0 => 'www.example.org',
    1 => 'www.example.org:443',
  ),