title: sender non-delivery notification while sending the email
body: <p>this is the command i am trying to send the email from command line.</p>
  
  <pre><code> echo "Test Email message body" | mail -s "Email test subject" sampleemail971@gmail.com
  </code></pre>
  
  <p>this is error i am getting while sending the mail. It shows mail has delivered but in mail i didn't receive any email.please help to send the email in postfix</p>
  
  <pre><code>Apr 20 15:52:42 igslt14-HP-Notebook postfix/pickup[25694]: 8FDABE20E93: uid=1000 from=&lt;igs-lt14@igslt14-HP-Notebook&gt;
  Apr 20 15:52:42 igslt14-HP-Notebook postfix/cleanup[25701]: 8FDABE20E93: message-id=&lt;20200420102242.8FDABE20E93@igslt14-HP-Notebook&gt;
  Apr 20 15:52:42 igslt14-HP-Notebook postfix/qmgr[25695]: 8FDABE20E93: from=&lt;igs-lt14@igslt14-HP-Notebook&gt;, size=396, nrcpt=1 (queue active)
  Apr 20 15:52:43 igslt14-HP-Notebook postfix/smtp[25703]: 8FDABE20E93: to=&lt;sampleemail971@gmail.com&gt;, relay=smtp.gmail.com[2404:6800:4003:c02::6c]:587, delay=0.83, delays=0.13/0.02/0.47/0.21, dsn=5.7.0, status=bounced (host smtp.gmail.com[2404:6800:4003:c02::6c] said: 530 5.7.0 Must issue a STARTTLS command first. f21sm723614pfn.71 - gsmtp (in reply to MAIL FROM command))
  Apr 20 15:52:43 igslt14-HP-Notebook postfix/cleanup[25701]: 960C3E20E94: message-id=&lt;20200420102243.960C3E20E94@igslt14-HP-Notebook&gt;
  Apr 20 15:52:43 igslt14-HP-Notebook postfix/qmgr[25695]: 960C3E20E94: from=&lt;&gt;, size=2569, nrcpt=1 (queue active)
  Apr 20 15:52:43 igslt14-HP-Notebook postfix/bounce[25704]: 8FDABE20E93: sender non-delivery notification: 960C3E20E94
  Apr 20 15:52:43 igslt14-HP-Notebook postfix/qmgr[25695]: 8FDABE20E93: removed
  Apr 20 15:52:43 igslt14-HP-Notebook postfix/local[25705]: 960C3E20E94: to=&lt;igs-lt14@igslt14-HP-Notebook&gt;, relay=local, delay=0.13, delays=0.05/0.02/0/0.06, dsn=2.0.0, status=sent (delivered to mailbox)
  Apr 20 15:52:43 igslt14-HP-Notebook postfix/qmgr[25695]: 960C3E20E94: removed
  </code></pre>
  
  <p>this is the file to configure to send the mail to email.please let me know what changes have to be made to send the email.</p>
  
  <pre><code># 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
  
  # See http://www.postfix.org/COMPATIBILITY_README.html -- default to 2 on
  # fresh installs.
  compatibility_level = 2
  
  # 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 = igslt14-HP-Notebook
  alias_maps = hash:/etc/aliases
  alias_database = hash:/etc/aliases
  mydestination = igslt14-HP-Notebook, igslt14-HP-Notebook, localhost.localdomain, localhost
  relayhost = [smtp.gmail.com]:587
  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
  </code></pre>