Zimbra - HaProxy

Help!
1

My configuration on haproxy:

global
log /dev/log local0
log /dev/log local1 notice
chroot /var/lib/haproxy
user haproxy
group haproxy
daemon

defaults
option dontlognull # Do not log connections with no requests
option redispatch # Try another server in case of connection failure
option contstats # Enable continuous traffic statistics updates
retries 3 # Try to connect up to 3 times in case of failure
timeout connect 5s # 5 seconds max to connect or to stay in queue
timeout http-keep-alive 1s # 1 second max for the client to post next request
timeout http-request 15s # 15 seconds max for the client to send a request
timeout queue 30s # 30 seconds max queued on load balancer
timeout tarpit 1m # tarpit hold tim
backlog 10000 # Size of SYN backlog queue
balance roundrobin # load balancing algorithm
mode tcp # protocol analyzer
option tcplog # log format
log global # log activation
timeout client 300s # client inactivity timeout
timeout server 300s # server inactivity timeout
default-server inter 3s rise 2 fall 3 # default check parameters

frontend Exchange_FrontEnd_HTTP
bind 192.168.201.15:80 name web
maxconn 10000
default_backend Exchange_BackEnd_HTTP

backend Exchange_BackEnd_HTTP
server SRV-EX01 192.168.201.235:80 maxconn 10000 check
p

frontend Exchange_FrontEnd_SSL
bind 192.168.201.15:443 name ssl
maxconn 10000
default_backend Exchange_BackEnd_SSL

backend Exchange_BackEnd_SSL
server SRV-EX01 192.168.201.235:443 maxconn 10000 check
p

frontend Exchange_FrontEnd_SMTP25
bind 192.168.201.15:25 name smtp
maxconn 10000
default_backend Exchange_BackEnd_SMTP25

backend Exchange_BackEnd_SMTP25
server SRV-EX01 192.168.201.235:25 maxconn 10000 check

frontend Exchange_FrontEnd_SMTP_Secure
bind 192.168.201.15:465 name smtpssl
maxconn 10000
default_backend Exchange_BackEnd_SMTP_Secure

backend Exchange_BackEnd_SMTP_Secure
server SRV-EX01 192.168.201.235:465 maxconn 10000 check

frontend Exchange_FrontEnd_IMAP
bind 192.168.201.15:143 name imap
maxconn 10000
default_backend Exchange_BackEnd_IMAP

backend Exchange_BackEnd_IMAP
server SRV-EX01 192.168.201.235:143 maxconn 10000 check

frontend Exchange_FrontEnd_IMAP_Secure
bind 192.168.201.15:993 name imapssl
maxconn 10000
default_backend Exchange_BackEnd_IMAP_Secure

backend Exchange_BackEnd_IMAP_Secure
server SRV-EX01 192.168.201.235:993 maxconn 10000 check

but does not receive mail. sends but does not receive e-mails
how to improve this configuration on balancing
Does zimbra work with haproxy? is this possible? configuration in zimbra?