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1.5.18 HAproxy Not making backend server down

currently i want HAproxy to switch to error page if the layer 7 is down. But it doesn’t do that. It will change to error file when layer 4 is down.
Current config CentOS 6, HAproxy 1.5.18. Back end is running Cpanel.

my config file
log local0 notice
maxconn 25000
user haproxy
group haproxy
tune.ssl.default-dh-param 2048

log global
mode http
option httplog
option dontlognull
option httpclose
option redispatch
retries 2
timeout connect 1000
timeout client 1000
timeout server 1000

IF no web server available

errorfile 503 /etc/haproxy/errorfiles/sorry.http
errorfile 400 /etc/haproxy/errorfiles/400.http

listen stats :8080
stats enable
stats hide-version
stats realm Loadbalanced\ Servers
stats uri /haproxy?stats
stats auth admin:admin

frontend https
bind *:80
bind *:443 ssl crt /etc/ssl/certs/XXX
redirect scheme https code 301 if !{ ssl_fc }
default_backend website

backend website
mode http
balance roundrobin
option httpchk
http-check expect status 200
http-check disable-on-404
server web01 XXX.XXX.XXX.XXX :443 check inter 5s fall 3 rise 2 ssl verify none

it keeps showing me the following text when the error happen

Elaborate what that means exactly.