This is my Nginx,conf

user www-data;
worker_processes auto;
pid /run/nginx.pid;

events {
workerconnections 768;
# multiaccept on;
}

http {

##
# Basic Settings
##

sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 65;
types_hash_max_size 2048;
# server_tokens off;

# 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 6;
# 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/*;

}

mail {

# See sample authentication script at:

# http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript

# auth_http localhost/auth.php;

# pop3_capabilities “TOP” “USER”;

# imap_capabilities “IMAP4rev1” “UIDPLUS”;

server {

listen localhost:110;

protocol pop3;

proxy on;

server {

listen localhost:143;

protocol imap;

proxy on;

}