I have known the reason. 2010/9/28 lhmwzy <lhmwzy at gmail.com>: > Why cancel the "secure_link_expires" directive ? > > 2010/9/27 Igor Sysoev <igor at sysoev.ru>: >> Changes with nginx 0.8.51 27 Sep 2010 >> >> *) Change: the "secure_link_expires" directive has been canceled. >> >