Article ID: 1093, created on Oct 6, 2008, last review on Mar 19, 2015

  • Applies to:
  • Plesk Automation 11.5
  • Plesk 11.0 for Windows
  • Plesk 11.5 for Windows


Sent email return with the error:

MailEnable: Message delivery has been delayed.


This message means that the SMTP connector is not configured correctly. The following setting should be correctly setup:

Mail Enable Administrator > Servers > localhost > Connectors > SMTP > Properties

  1. DNS server should be valid. It must resolve any correct host name.
  2. Fully Qualified Domain Name (FQDN) should be properly resolved in DNS.
  3. Bound IPs for SMTP should have correctly resolvable PTR DNS records (Mail Enable Administrator > Servers > localhost > Connectors > SMTP > Properties > Inbound tab)
    This can be checked using

    Go to Reverse DNS lookup section and type your IP(s) that are bound by SMTP. Request should return a valid host name or domain.

  4. If these parameters are set up correctly, the file should also be correct:

    "%plesk_dir%\Mail Servers\Mail Enable\Config\ADDRESS-MAP.TAB"

    The first line should be the following:

    [SMTP:*] 0 System
  5. Check, if your server can access remote SMTP servers.

    You can check it using telnet tool

    C:\> telnet 25 Trying Connected to Escape character is '^]'. 220 ESMTP YSmtp service ready

    Connection output should be similar.

Search Words

Message delivery has been delayed


Plesk mail flow issues

Message delivery has been delayed.

Reason: 550 OU-002

Reason: 550 OU-002 (COL004-MC6F28

a914db3fdc7a53ddcfd1b2db8f5a1b9c 56797cefb1efc9130f7c48a7d1db0f0c 33a70544d00d562bbc5b17762c4ed2b3 caea8340e2d186a540518d08602aa065 e0aff7830fa22f92062ee4db78133079 514af229ae32522202a910a2649c80fb 85a92ca67f2200d36506862eaa6ed6b8 bd7fc88cf1b01f097749ae6f87272128 46a8e394d6fa13134808921036a34da8

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