E-mails are rejecting with "Message rejected as spam by Content Filtering" message.

Issue

• Local e-mails are working fine on RHEL system. After sending remote e-mails, getting following messages:

  Nov  3 18:08:22 test02 postfix/smtp[32527]: 0838039A: to=<root@test.com>, relay=relay.test.com[xx.xx.xx.xx]:25, delay=0.2, delays=0/0.01/0.01/0.18, dsn=2.6.0, status=sent (250 2.6.0 <20141103123822.083338039A@test.com> [InternalId=118677] Queued mail for delivery)
  Nov  3 18:08:22  rheltest02 postfix/qmgr[32369]: 0838039A: removed
  Nov  3 18:08:27  rheltest02 postfix/smtp[32526]: 01580392: to=<user@remote.com>, orig_to=<root@test.com>, relay=relay.test.com[xx.xx.xx.xx]:25, delay=5.1, delays=0.01/0.01/0.01/5.1, dsn=5.7.1, status=bounced (host relay.test.com[xx.xx.xx.xx] said: 550 5.7.1 Message rejected as spam by Content Filtering. (in reply to end of DATA command))