nginx loops between www and non-www versions, Please help with nginx config

Need to resolve this asap, this is basic setup but does not work, please have a look at config files below. site is looping between www and non-www until firefox of chrome stops it:

Firefox has detected that the server is redirecting the request for this address in a way that will never complete.

here is my nginx.conf

user xxxxxxx; worker_processes 1; pid /run/nginx.pid; include /etc/nginx/modules-enabled/*.conf;

events { worker_connections 1024; multi_accept on; }

http {

##
# Basic Settings
##

sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 15;
types_hash_max_size 2048;
server_tokens off;
client_max_body_size 16m;

# server_names_hash_bucket_size 64;
# server_name_in_redirect off;

include /etc/nginx/mime.types;
default_type application/octet-stream;

##
# SSL Settings
##

ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
ssl_prefer_server_ciphers on;

##
# Logging Settings
##

access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;

##
# Gzip Settings
##

gzip on;
gzip_disable "msie6";

# gzip_vary on;
gzip_proxied any;
gzip_comp_level 2;
# gzip_buffers 16 8k;
# gzip_http_version 1.1;
gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

##
# Virtual Host Configs
##

include /etc/nginx/conf.d/*.conf;

include /etc/nginx/sites-enabled/*;

server { listen 80 default_server; listen [::]:80 default_server; server_name _; return 444; }

}