Mails sent with delay on the Plesk server: Blocked MTA-BLOCKED {TempFailedInbound}

Symptoms

• After installing Plesk Email Security extension, emails are sent with a delay or not sent at all.

• The following messages are logged in /var/log/maillog:

  CONFIG_TEXT: mavis[18174]: (18174-06) Blocked MTA-BLOCKED {TempFailedInbound}
  greylisting filter[18496]: Starting greylisting filter...
  /usr/lib/plesk-9.0/psa-pc-remote[544]: handlers_stderr: DEFER
  /usr/lib/plesk-9.0/psa-pc-remote[544]: DEFER during call 'grey' handler
  /usr/lib/plesk-9.0/psa-pc-remote[544]: Message aborted.
  postfix/smtp[17829]: 5BBB9302939: to=john_doe@example.com, relay=127.0.0.1[127.0.0.1]:10024, delay=3.9, delays=2.3/0/0/1.6, dsn=4.7.1, status=deferred (host 127.0.0.1[127.0.0.1] said: 451 4.7.1 id=18174-06 - Temporary MTA failure on relaying, from MTA(smtp:[127.0.0.1]:10025): 451 4.7.1 Service unavailable - try again later (in reply to end of DATA command))

• Greylisting is enabled:

  # /usr/local/psa/bin/grey_listing --info-server | grep 'Grey listing checking'
  Grey listing checking enabled

Cause

Greylisting is not supported by Plesk Email Security.

Resolution

1. Connect to the Plesk server via SSH.

2. Disable Greylisting:

   # /usr/local/psa/bin/grey_listing -u -status off