Only HTTPS 502,521 error

Hello guys,
I’am trying to setup haproxy on Ubuntu 16.04 Haproxy 1.7v with ssl only.I have A record in cloudflare to ip where is loadbalancer.Check my haproxy.cfg

log /dev/log local0
log /dev/log local1 notice
chroot /var/lib/haproxy
stats socket /run/haproxy/admin.sock mode 660 level admin
stats timeout 30s
user haproxy
group haproxy
maxconn 5000
tune.ssl.default-dh-param 2048

    # Default SSL material locations
    ca-base /etc/ssl/certs
    crt-base /etc/ssl/private

    # Default ciphers to use on SSL-enabled listening sockets.
    # For more information, see ciphers(1SSL). This list is from:
    # An alternative list with additional directives can be obtained from
    ssl-default-bind-options no-sslv3

log global
mode http
option httplog
option dontlognull
timeout connect 5000
timeout client 50000
timeout server 50000
stats enable
stats hide-version
stats uri /stats
stats realm Haproxy\ Statistics
stats auth admin:123$
stats refresh 5s

frontend UP-Proxy
bind *:443 ssl crt /etc/haproxy/cert/server.pem

acl site_dead nbsrv(LoadBalancer) lt 1
tcp-request connection reject if site_dead
monitor-uri /haproxy?monitor

default_backend LoadBalancer
backend LoadBalancer
balance roundrobin
option redispatch 1
cookie SERVERID insert indirect nocache

server up130 cookie 130 check fall 3 rise 2
server up153 cookie 153 check fall 3 rise 2

When i try to request site cloudflare throw 521 or 502 (Bad gateway) Please Help :frowning: