It looks while giving details about problem I found the qcause of issue, its small bug in the entries created in /etc/postfix/main.cf
They are :
smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination,reject_non_fqdn_sender,reject_non_fqdn_recipient,reject_unknown_recipient_domain,reject_rbl_clientzen.spamhaus.org,reject_rbl_clientbl.spamcop.net,reject_rbl_clientdnsbl.sorbs.net,check_policy_service unix:private/spfpolicy
But should be :
smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination,reject_non_fqdn_sender,reject_non_fqdn_recipient,reject_unknown_recipient_domain,reject_rbl_client zen.spamhaus.org,reject_rbl_client bl.spamcop.net,reject_rbl_client dnsbl.sorbs.net,check_policy_service unix:private/spfpolicy
Posting here so that can help others.