Postfix deferred transport

[gialby]

i have some problem to configure post fix..
I think that i finish the configuration, but when i send an e-mail fromn user to another user i receive this error message:

"delivery temporarily suspended: deferred transport"

i don't know where is the problem

This is my main.cf, somebody can help me?
Thanks

Gianluca Albanese

main.cf

readme_directory = /usr/share/doc/packages/postfix/README_FILES
inet_protocols = all
biff = no
mail_spool_directory = /var/mail
canonical_maps = hash:/etc/postfix/canonical
virtual_alias_maps = hash:/etc/postfix/virtual
virtual_alias_domains = hash:/etc/postfix/virtual
relocated_maps = hash:/etc/postfix/relocated
transport_maps = hash:/etc/postfix/transport
sender_canonical_maps = hash:/etc/postfix/sender_canonical
masquerade_exceptions = root
masquerade_classes = envelope_sender, header_sender, header_recipient
myhostname = mail.linux
program_directory = /usr/lib/postfix

command_directory = /usr/sbin


mydestination = $myhostname, localhost.$mydomain
mynetworks = 132.145.0.0/16
defer_transports = smtp
disable_dns_lookups = no
mailbox_command =
mailbox_transport =
strict_8bitmime = no
disable_mime_output_conversion = no
smtpd_sender_restrictions = hash:/etc/postfix/access
strict_rfc821_envelopes = no
smtpd_recipient_restrictions = permit_mynetworks,reject_unauth_destination
smtp_sasl_auth_enable = no
smtpd_sasl_auth_enable = no
smtpd_use_tls = no
smtp_use_tls = no
alias_maps = hash:/etc/aliases
mailbox_size_limit = 0
message_size_limit = 10240000
smtpd_banner = Linux Server Mail by Gialby
recipient_canonical_maps = hash:/etc/postfix/recipinet_canonical
mail_name = mail.linux