mails not getting delivered to the external domains

Dear Experts:

We are maintaiing zimbra mail server zcs-Network-edition in our network, for the external delivery we use the upstream MTA of the service provider the service provider also takescare of email security (firewall).

Presently the file being created under /opt/zimbra/postfix/conf/relay_password and put the maps for smarthost relays in it. Just few hours ago upgraded to zcs-Network-8.0.3 and upgrade got successful but the problem is we are not able to send the email to the external domains .

Have tried all the below

Create file /opt/zimbra/postfix/conf/relaybysender and put the maps for smarthost relays in

postconf -e smtp_sasl_password_maps=hash:/opt/zimbra/postfix/conf/relay_passwords

postmap hash:/opt/zimbra/postfix/conf/relay_passwords

postconf -e smtp_sasl_auth_enable=yes
postconf -e smtp_tls_security_level = may


postconf -e smtp_cname_overrides_servername=no
 
Reload postfix
zmmtactl restart
 
 still the message bounces  with the below message
      The mail system

<myname@gmail.com>: host smtp.looouix.in[115.112.241.17] said: 530
    Authentication required (in reply to MAIL FROM command)

Please suggest to fix this so that I can send mails to external domains using he upstream MTA of service provider. Thanks in advance.