懒得翻译了，反正按中文互联网上的什么改权限这的那的不管用折腾了好久，下面这段话save my ass.
I experienced the same problem and it was due to SELinux.
To check if SELinux is running:
To disable SELinux until next reboot:
# setenforce Permissive
Restart Nginx and see if the problem persists. If you would like to permanently alter the settings you can edit
If SELinux is your problem you can run the following to allow nginx to serve your www directory (make sure you turn SELinux back on before testing this. i.e,
# setenforce Enforcing)
# chcon -Rt httpd_sys_content_t /path/to/www
If you're still having issues take a look at the boolean flags in
getsebool -a, in particular you may need to turn on
httpd_can_network_connect for network access
# setsebool -P httpd_can_network_connect on
For me it was enough to allow http to serve my www directory.