ホストをウェブメールに使用しています。メールはyahooや他のwebメールには送れますが、Gmailやgoogleアプリには送れません。エラー：
Mail delivery failed: returning message to sender
tinhphaistc@gmail.com
SMTP error from remote mail server after end of data:
host gmail-smtp-in.l.google.com [74.125.129.26]:
550-5.7.1 [103.3.245.71 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. hb2si3576957pac.234 - gsmtp