GMAIL EMAIL ALWAYS BOUNCE BACK

[aspangilinan]

HI to all,

i have one problem, for gmail email issue, we cannot send to gmail domain. 

here's the error

host gmail-smtp-in.l.google.com[173.194.77.27]
    said: 550-5.7.1 [122.52.109.199       1] Our system has detected an unusual
    rate of 550-5.7.1 unsolicited mail originating from your IP address. To
    protect our 550-5.7.1 users from spam, mail sent from your IP address has
    been blocked. 550-5.7.1 Please visit
    http://www.google.com/mail/help/bulk_mail.html to review 550 5.7.1 our Bulk
    Email Senders Guidelines. rw5si19289121obb.192 - gsmtp (in reply to end of
    DATA command)

may i know how to fix this problem

thanks please help me.

[christian]

Perhaps for one of the reasons you where already black-listed in the past 

If you don't learn from this and can keep your users from spamming (or acting in a way that is perceived as spam), next time you ask for you IP to be removed from the black-list, they may just refuse 

[aspangilinan]

may i know to prevent this problem. thanks.

[christian]

Assuming you are not real spammer    it means that at least one of your users has some trojan or unwanted program running on his workstation (well, check this is not running on Zentyal itself).

If you prevent users to directly send mail to internet and therefore make use of Zentyal as SMTP server mandatory, you should be able to look at mail log an determine who is spamming from inside.
I can't comment on how to clean-up workstation sorry.

Using proxy + anti-virus should also minimize such risk