Never get authentication mail from gitlab

[Rutvik Prajapati]

I installed gitlab in my ubuntu 14.04 and configure it. 

I think everything is working correctly accept mail system.  I always get 

"said: 554 Sending address not accepted due to spam filter (in reply to MAIL FROM command))"

or status=blouced (unkown user "<rutvik.prajapati>")

This is my configuration in 

1) /etc/postfix/main.cf 

smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination

myhostname = <myhost>.com

alias_maps = hash:/etc/aliases

alias_database = hash:/etc/aliases

mydestination = mail.<mymailserver>.com, localhost.localdomain, localhost

relayhost =

mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128

mailbox_size_limit = 0

recipient_delimiter = +

inet_interfaces = all

inet_protocols = all

myorigin = /etc/mailname

I also tried with custom configuration in /etc/gitlat/gitlab.rb file here it is : 

 gitlab_rails['smtp_enable'] = true

 gitlab_rails['smtp_address'] = "<my smtp server>"

 gitlab_rails['smtp_port'] = <my port>

 gitlab_rails['smtp_user_name'] = "<user_name>"

 gitlab_rails['smtp_password'] = "<password>"

 gitlab_rails['smtp_domain'] = "<my domaun>"

 gitlab_rails['smtp_authentication'] = "login"