Passenger logging agent error in deployment with passenger+nginx

I install passenger+nginx on centos 6.5 by:

gem install passenger
passenger-install-nginx-module

everything is ok during the installation, then I run:

sudo ~/nginx/sbin/nginx

and get the error message:
nginx: [alert] Unable to start the Phusion Passenger watchdog because it
encountered the following error during startup: Unable to start the
Phusion Passenger logging agent: it seems to have crashed during startup
for an unknown reason, with exit code 1 (-1: Unknown error)

Also I run:

sudo ~/nginx/sbin/nginx -t

get the same message:

nginx: the configuration file /home/lq/nginx/conf/nginx.conf syntax is
ok
nginx: [alert] Unable to start the Phusion Passenger watchdog because it
encountered the following error during startup: Unable to start the
Phusion Passenger logging agent: it seems to have crashed during startup
for an unknown reason, with exit code 1 (-1: Unknown error)
nginx: configuration file /home/lq/nginx/conf/nginx.conf test is
successful

If I run nginx or passenger standalone, both of them are ok. But it
seems they can’t work together.
Can anyone tell me something about it? thanks!

My system is:

ruby 2.1.0
rails 4.2.1
gem 2.4.6
passenger 5.0.5
nginx 1.6.2