Recently I tried to set up a new email server using iRedMail on Lubuntu.
The mail server workes very well when email conversation is in the same domain.
But when a user tries to send email to some of the most popular domains like gmail, hotmail or yahoo; all the emails are blocked.
I tried to send an email to my gmail account, this is error response I got.
host gmail-smtp-in.l.google.com[74.125.130.27] said: 550-5.7.1 [XX.XX.XX.XX 12] Our system has detected that this message is 550-5.7.1 likely unsolicited mail. To reduce the amount of spam sent to Gmail, 550-5.7.1 this message has been blocked. Please visit 550-5.7.1 http://support.google.com/mail/bin/answer.py?hl=en&answer=188131 for 550 5.7.1 more information. g12si14338274pat.29 - gsmtp (in reply to end of DATA command)
The XX.XX.XX.XX part is my IP.
Latter I found that my ip is added to black list at Spamhaus. I requested them to remove my IP. They accepted my request. It also suggested to activate the smtp authentication.
But it was already set to yes as given below.
smtpd_sasl_auth_enable = yes
After a few hours, I again tried to send a mail to my gmail account, again same msg is replied. When I check the spamhaus database, my ip is also there.
Please help.