I have an Ubuntu server with Postfix and Dovecot IMAP and they're not receiving mail. My Postfix config is

# See /usr/share/postfix/main.cf.dist for a commented, more complete version


# Debian specific: Specifying a file name will cause the first
# line of that file to be used as the name. The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname

smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h

readme_directory = no

# TLS parameters
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.

myhostname = cheesecakebb.org
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
mydestination = cheese-ubuntu, localhost.localdomain, localhost cheesecakebb.org
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 100000
recipient_delimiter = +
inet_interfaces = all
default_transport = smtp
relay_transport = smtp
inet_protocols = all
myorigin = /etc/mailname
relayhost =
And the Dovecot config:

disable_plaintext_auth = no
mail_privileged_group = mail
mail_location = mbox:~/mail:INBOX=/var/mail/%u
userdb {
driver = passwd
}
passdb {
args = %s
driver = pam
}
protocols = imap

protocol imap {
mail_plugins = " autocreate"
}
plugin {
autocreate = Trash
autocreate2 = Sent
autosubscribe = Trash
autosubscribe2 = Sent
}

service auth {
unix_listener /var/spool/postfix/private/auth {
group = postfix
mode = 0660
user = postfix
}
}
ssl=no