Postfix can't send email to the same domain name email address as the droplet

I have been researching for 3days but haven’t find the solution for this email issue.

I use Postfix to send out email on my droplet which is working fine for all email addresses but not for the email address that I assigned to the droplet. I have tried http://stackoverflow.com/questions/18377813/postfix-status-bounced-unknown-user-myuser and all other suggestions I found online but nothing worked.

Here is my etc/postfix/main.cf

# 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.

smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = goodnightjournal.com
alias_maps = hash:/etc/aliases
# virtual_alias_maps = hash:/etc/postfix/virtual
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = localhost
relayhost =
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = loopback-only
inet_protocols = all

and I’m getting this error message on sending email to o@goodnightjournal.com from my contact form on the site.

Feb 23 01:30:41 goodnightjournal postfix/pickup[17494]: 492A4185557: uid=33 from=<www-data>
Feb 23 01:30:41 goodnightjournal postfix/cleanup[17713]: 492A4185557: message-id=<d2b17d8f8fb99f252a50a823d0e8cbdb@goodnightjournal.com>
Feb 23 01:30:41 goodnightjournal postfix/qmgr[17105]: 492A4185557: from=<www-data@104.236.98.136>, size=706, nrcpt=1 (queue active)
Feb 23 01:30:41 goodnightjournal postfix/smtp[17715]: 492A4185557: to=<o@goodnightjournal.com>, relay=smtp.secureserver.net[68.178.213.203]:25, delay=0.48, delays=0.01/0/0.21/0.25, dsn=5.2.0, status=bounced (host smtp.secureserver.net[68.178.213.203] said: 550 5.2.0 <www-data@104.236.98.136> From: Domain is invalid. Please provide a valid From: IB506  <http://x.co/srbounce> (in reply to end of DATA command))
Feb 23 01:30:41 goodnightjournal postfix/cleanup[17713]: BEB9D185558: message-id=<20170223063041.BEB9D185558@goodnightjournal.com>
Feb 23 01:30:41 goodnightjournal postfix/qmgr[17105]: BEB9D185558: from=<>, size=2817, nrcpt=1 (queue active)
Feb 23 01:30:41 goodnightjournal postfix/bounce[17716]: 492A4185557: sender non-delivery notification: BEB9D185558
Feb 23 01:30:41 goodnightjournal postfix/qmgr[17105]: 492A4185557: removed
Feb 23 01:30:41 goodnightjournal postfix/error[17718]: BEB9D185558: to=<www-data@104.236.98.136>, relay=none, delay=0.02, delays=0.01/0.01/0/0, dsn=5.1.3, status=bounced (bad address syntax)
Feb 23 01:30:41 goodnightjournal postfix/qmgr[17105]: BEB9D185558: removed