Article ID: 121456, created on May 4, 2014, last review on May 10, 2014

  • Applies to:
  • Plesk 11.0 for Windows


Emails bounced back with the following delivery failure description:

MailEnable: Message could not be delivered to some recipients.
Reason: Remote SMTP Server Returned: 450 4.7.1 Client host rejected: cannot find your hostname


MailEnable misconfiguration.


  1. Check the "Default mail domain name" setup in MailEnable:

    • Open MailEnable Management > Servers > localhost > connectors > SMTP > right click to open Properties.

    • Switch to the General tab > check "Default mail domain name", say you have the specified.
  2. Make sure that the can be reversed correctly. Do the following test:

    > nslookup
    Non-authoritative answer:
    Address: A.B.C.D
    > nslookup A.B.C.D
    Non-authoritative answer:     name =
    Authoritative answers can be found.
    > ping
    ping: unknown host

    The output above shows that host IP reverse lookup test fails.

    This test checks all the local machine's TCP/IP addresses for reverse DNS lookup. Some mail servers perform a reverse lookup on you IP address. You need to ensure that external IP addresses facilitate a reverse lookup or mail servers (like Yahoo and Hotmail) will reject your mail.

  3. Additionally please run the "%plesk_dir%\Mail Servers\Mail Enable\Bin\MEDIAG.exe" - tool that will show you the diagnostic report. This utility is designed to assist you in configuring MailEnable. It validates your configuration and assists you in configuring MailEnable services.

Search Words

Emails bounced

SMTP Server Returned: 450 4.7.1

Message could not be delivered to some recipients

Client host rejected: cannot find your hostname

a914db3fdc7a53ddcfd1b2db8f5a1b9c 56797cefb1efc9130f7c48a7d1db0f0c 514af229ae32522202a910a2649c80fb 85a92ca67f2200d36506862eaa6ed6b8 bd7fc88cf1b01f097749ae6f87272128

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