Issue with 502 Gateway - Cors issue ?

[smalldragoon]

Hi All,
I set a basic config with pfsense as SSL termination.
I'm using a CMS on a standard Apache / PHP / Mysql system.
Reaching the website, I it half working as I have on a regular basis some 502 bad gateway errors and seems linked to cors issue ?

Am I right saying this ?
If so , I found this article in the forum for CORS :

https://forum.netgate.com/topic/171678/enabling-cors-in-haproxy?_=1715866714636

But wanted before going this way to double check if it is really my issue as my other sites seems not to be problematic.
Issue is on "stream", "main" and "moodle" are ok

Here is for ref my haproxy .conf

# Automaticaly generated, dont edit manually.
# Generated on: 2024-05-03 09:36
global
        maxconn                 5000
        log                     /var/run/log    syslog  debug
        stats socket /tmp/haproxy.socket level admin  expose-fd listeners
        uid                     80
        gid                     80
        nbthread                        1
        hard-stop-after         15m
        chroot                          /tmp/haproxy_chroot
        daemon
        tune.ssl.default-dh-param       2048
        log-send-hostname               MAIN
        server-state-file /tmp/haproxy_server_state

listen HAProxyLocalStats
        bind 127.0.0.1:2200 name localstats
        mode http
        stats enable
        stats refresh 10
        stats admin if TRUE
        stats show-legends
        stats uri /haproxy/haproxy_stats.php?haproxystats=1
        timeout client 5000
        timeout connect 5000
        timeout server 5000

frontend Main_FrontEnd
        bind                    MY_PUBLIC_IP:443 name MY_PUBLIC_IP:443   ssl crt-list /var/etc/haproxy/Main_FrontEnd.crt_list
        mode                    http
        log                     global
        option                  httplog
        option                  http-keep-alive
        option                  forwardfor
        acl https ssl_fc
        http-request set-header         X-Forwarded-Proto http if !https
        http-request set-header         X-Forwarded-Proto https if https
        timeout client          30000
        acl                     Direct  var(txn.txnhost) -m str -i cleafy.MY_DOMAIN.com
        acl                     Stream  var(txn.txnhost) -m str -i cleafystream.MY_DOMAIN.com
        acl                     Wordpress       var(txn.txnhost) -m str -i wordpress.MY_DOMAIN.com
        acl                     MoodleSSL       var(txn.txnhost) -m str -i moodle.MY_DOMAIN.com
        acl                     aclcrt_Main_FrontEnd    var(txn.txnhost) -m reg -i ^([^\.]*)\.MY_DOMAIN\.com(:([0-9]){1,5})?$
        http-request set-var(txn.txnhost) hdr(host)
        use_backend Direct_ipvANY  if  Direct aclcrt_Main_FrontEnd
        use_backend Stream_ipvANY  if  Stream aclcrt_Main_FrontEnd
        use_backend Wordpress_ipvANY  if  Wordpress aclcrt_Main_FrontEnd
        use_backend Moodle-SSL_ipvANY  if  MoodleSSL aclcrt_Main_FrontEnd


backend Direct_ipvANY
        mode                    http
        id                      110
        log                     global
        timeout connect         30000
        timeout server          30000
        retries                 3
        load-server-state-from-file     global
        server                  Moodle-SSL X.Y.Z.114:80 id 101 check inter 1000

backend Stream_ipvANY
        mode                    http
        id                      111
        log                     global
        timeout connect         30000
        timeout server          30000
        retries                 3
        load-server-state-from-file     global
        server                  Moodle-SSL X.Y.Z.175:80 id 101 check inter 1000

backend Wordpress_ipvANY
        mode                    http
        id                      112
        log                     global
        timeout connect         30000
        timeout server          30000
        retries                 3
        load-server-state-from-file     global
        server                  Moodle-SSL X.Y.Z.119:80 id 101 check inter 1000

backend Moodle-SSL_ipvANY
        mode                    http
        id                      100
        log                     global
        timeout connect         30000
        timeout server          30000
        retries                 3
        load-server-state-from-file     global
        server                  Moodle-SSL X.Y.Z.145:80 id 101 check inter 1000

Thanks for your insights !