Exchange 2010 and setup through haproxy

Hi, I was wondering if someone can point me in the right direction of resolving an exchange CAS server setup. When using owa we receive error “The custom error module does not recognize this error” has anyone come across this before? We have replaced an old TMG with pfsense and haproxy integrated. Thanks

My config below

Automaticaly generated, dont edit manually.

Generated on: 2020-08-06 18:23

global

frontend HTTPS_LISTENER_12
bind 10.200.2.12:443 name 10.200.2.12:443 no-tlsv10 ssl crt-list /var/etc/haproxy/HTTPS_LISTENER_12.crt_list
mode http
log global
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 CAS_PATH_ACL var(txn.txnpath) -m beg -i /public /OWA /Exchange /ecp /Microsoft-Server-ActiveSync /rpc /oab /autodiscover /ews
acl OWA_PATH_ACL var(txn.txnpath) -m beg -i /ews/mrsproxy.svc /ews/exchange.asmx/wssecurity /autodiscover/autodiscover.svc/wssecurity /autodiscover/autodiscover.svc
acl PATH_SLASH_ACL var(txn.txnpath) -m str -i /
acl HOST_MAIL_ACL var(txn.txnhost) -m str -i mail.domain.com
acl AUTO_NAME_ACL var(txn.txnhost) -m str -i autodiscover.domain.com
acl AUTO_PATH_ACL var(txn.txnpath) -m beg -i /rpc /oab /ews /autodiscover
acl aclcrt_HTTPS_LISTENER_12 var(txn.txnhost) -m reg -i ^([^.]*).ballyvesey.com(:([0-9]){1,5})? acl aclcrt_HTTPS_LISTENER_12 var(txn.txnhost) -m reg -i ^domain\.com(:([0-9]){1,5})?
http-request set-var(txn.txnpath) path
http-request set-var(txn.txnhost) hdr(host)
http-request redirect location /OWA/ code 302 if PATH_SLASH_ACL HOST_MAIL_ACL aclcrt_HTTPS_LISTENER_12
use_backend OWA_EX2K10_ipvANY if CAS_PATH_ACL aclcrt_HTTPS_LISTENER_12
use_backend OWA_SERVER_ipvANY if OWA_PATH_ACL aclcrt_HTTPS_LISTENER_12
use_backend OWA_EX2K10_ipvANY if AUTO_NAME_ACL AUTO_PATH_ACL aclcrt_HTTPS_LISTENER_12
use_backend OWA_EX2K10_ipvANY if aclcrt_HTTPS_LISTENER_12

backend OWA_EX2K10_ipvANY
mode http
id 105
log global
balance roundrobin
timeout connect 30000
timeout server 30000
retries 3
server GG-EXCAS01 192.168.127.16:443 id 106 ssl check inter 1000 verify none
server GG-EXCAS02 192.168.127.18:443 id 107 ssl check inter 1000 verify none

backend OWA_SERVER_ipvANY
mode http
id 108
log global
timeout connect 30000
timeout server 30000
retries 3
option httpchk OPTIONS /
server gg-exhyb01 192.168.127.56:443 id 109 ssl check inter 1000 verify none