How fix for email authentication failure in postfix?

Error solution : -

Check port in

$ sudo nano /etc/postfix/main.cf
myhostname = ns1.example.com
alias_maps = hash:/etc/aliases
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 your IP

  • Restart Postfix
    $ sudo systemctl restart postfix