sudo cat /var/log/audit/audit.log | grep nginx | grep denied
=>
type=AVC msg=audit(1472992700.903:5853): avc: denied { name_connect } for pid=18318 comm="nginx" dest=3000 scontext=system_u:system_r:httpd_t:s0 tcontext=system_u:object_r:ntop_port_t:s0 tclass=tcp_socket
Solution:
chcon -Rt httpd_sys_content_t /var/www/clubs/
setsebool -P httpd_can_network_connect 1