If its open to transfer to it could be another issue. FOr example retainers have to be hired and not selling anything, you must leave your FC, and other issues. They are listed when you attempt the transfer and if it fails for whatever reason it usually states why, so you can fix it.
Hope this helps, if not I'm not sure. its possible that the world is full, if so try again during a non-peak time (ie: early morning or very late late at night and not on a weekend)