==== Required information ====
- iRedMail version: 0.8.4
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): LDAP
- Linux/BSD distribution name and version: Redhat Linux 6.4
- Related log if you're reporting an issue:
====
Output of postconf -n

alias_database = hash:/etc/postfix/aliases
alias_maps = hash:/etc/postfix/aliases
allow_min_user = no
allow_percent_hack = no
biff = no
bounce_queue_lifetime = 4h
broken_sasl_auth_clients = yes
command_directory = /usr/sbin
config_directory = /etc/postfix
content_filter = smtp-amavis:[127.0.0.1]:10024
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
delay_warning_time = 0h
disable_vrfy_command = yes
enable_original_recipient = no
home_mailbox = Maildir/
html_directory = no
inet_interfaces = all
inet_protocols = ipv4
mail_owner = postfix
mailbox_command = /usr/libexec/dovecot/deliver
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
maximal_backoff_time = 4000s
maximal_queue_lifetime = 4h
message_size_limit = 15728640
minimal_backoff_time = 300s
mydestination = $myhostname, localhost, localhost.localdomain, localhost.$myhostname
mydomain = acalschool.com
myhostname = mail.acalschool.com
mynetworks = 127.0.0.0/8
mynetworks_style = subnet
myorigin = mail.acalschool.com
newaliases_path = /usr/bin/newaliases.postfix
proxy_read_maps = $canonical_maps $lmtp_generic_maps $local_recipient_maps $mydestination $mynetworks $recipient_bcc_maps $recipient_canonical_maps $relay_domains $relay_recipient_maps $relocated_maps $sender_bcc_maps $sender_canonical_maps $smtp_generic_maps $smtpd_sender_login_maps $transport_maps $virtual_alias_domains $virtual_alias_maps $virtual_mailbox_domains $virtual_mailbox_maps $smtpd_sender_restrictions
queue_directory = /var/spool/postfix
queue_run_delay = 300s
readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES
recipient_bcc_maps = proxy:ldap:/etc/postfix/ldap/recipient_bcc_maps_user.cf, proxy:ldap:/etc/postfix/ldap/recipient_bcc_maps_domain.cf
recipient_delimiter = +
relay_domains = $mydestination, proxy:ldap:/etc/postfix/ldap/relay_domains.cf
sample_directory = /usr/share/doc/postfix-2.6.6/samples
sender_bcc_maps = proxy:ldap:/etc/postfix/ldap/sender_bcc_maps_user.cf, proxy:ldap:/etc/postfix/ldap/sender_bcc_maps_domain.cf
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtp_data_init_timeout = 240s
smtp_data_xfer_timeout = 600s
smtpd_data_restrictions = reject_unauth_pipelining
smtpd_helo_required = yes
smtpd_helo_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_non_fqdn_helo_hostname, reject_invalid_helo_hostname, check_helo_access pcre:/etc/postfix/helo_access.pcre
smtpd_recipient_restrictions = reject_unknown_sender_domain, reject_unknown_recipient_domain, reject_non_fqdn_sender, reject_non_fqdn_recipient, reject_unlisted_recipient, check_policy_service inet:127.0.0.1:7777, permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination, check_policy_service inet:127.0.0.1:10031
smtpd_reject_unlisted_recipient = yes
smtpd_reject_unlisted_sender = yes
smtpd_sasl_auth_enable = yes
smtpd_sasl_authenticated_header = no
smtpd_sasl_local_domain =
smtpd_sasl_path = ./dovecot-auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
smtpd_sender_login_maps = proxy:ldap:/etc/postfix/ldap/sender_login_maps.cf
smtpd_sender_restrictions = permit_mynetworks, reject_sender_login_mismatch, permit_sasl_authenticated
smtpd_tls_CAfile = /etc/pki/tls/certs/iRedMail_CA.pem
smtpd_tls_cert_file = /etc/pki/tls/certs/iRedMail_CA.pem
smtpd_tls_key_file = /etc/pki/tls/private/iRedMail.key
smtpd_tls_loglevel = 0
smtpd_tls_security_level = may
swap_bangpath = no
tls_random_source = dev:/dev/urandom
transport_maps = proxy:ldap:/etc/postfix/ldap/transport_maps_user.cf, proxy:ldap:/etc/postfix/ldap/transport_maps_domain.cf
unknown_local_recipient_reject_code = 550
virtual_alias_domains =
virtual_alias_maps = proxy:ldap:/etc/postfix/ldap/virtual_alias_maps.cf, proxy:ldap:/etc/postfix/ldap/virtual_group_maps.cf, proxy:ldap:/etc/postfix/ldap/virtual_group_members_maps.cf, proxy:ldap:/etc/postfix/ldap/catchall_maps.cf
virtual_gid_maps = static:2000
virtual_mailbox_base = /var/vmail
virtual_mailbox_domains = proxy:ldap:/etc/postfix/ldap/virtual_mailbox_domains.cf
virtual_mailbox_maps = proxy:ldap:/etc/postfix/ldap/virtual_mailbox_maps.cf
virtual_minimum_uid = 2000
virtual_transport = dovecot
virtual_uid_maps = static:2000

I have been sending emails and receive email from my iRedMail server through webmail to different accounts without any problem, but when I am trying to connect to the server through Thunderbird it fails, Similarly tail -f /var/log/maillog is not showing any sign of connection from thunderbird.
I have also disabled the firewall but it didn't seem to solve the problem.
I would really appreciate a prompt reply and help on this matter.
Thanks
Hashir