Wednesday, February 24, 2016

Error 400 4.4.7 Message Delayed Exchange Server 2010

MS Exchange Server is an email-based collaborative communications server used mostly in mid-scale and large-scale organizations. Mailbox server role is the common server role that is at the core of an Exchange Organization and Mailbox servers are those servers on which mailbox server role is installed. Sometimes user gets an error where the mail is stuck in the queue and it is not delivered to some domain displaying 400 4.4.7 Message Delayed. The blog will be discussing the possible solution for the same error.

Mailbox Server Role in Exchange Server 2010

In Microsoft Exchange Server 2010, the Mailbox server role is one of several server roles that we can install & configure on a server running Windows Server 2008. Mailbox servers on which Mailbox server role is installed perform functions like:
  • Host Mailbox Databases
  • Provide Email Storage
  • Calculate Email Address Policies
  • Provide Messaging Records Management (MRM) and Retention Policies

Error 400 4.4.7 Message Delayed

When a user tries to send a mail to some domain from an account synchronized with MS Exchange Server, we get an error that message has not been delivered yet or delay in delivery of the mail. This error is called ‘400 4.4.7 message delayed’ and one example of such error is given below:

Possible Solution

We need to make sure that the domains where we are trying to send mail are valid domains. When a mail server sends out a mail to another SMTP domain (mail server), the errors are associated with either the source mail server or the destination mail server.
Suppose a sender sends the mail to a receiver and some situations may occur like these: Sender’s mail server is missing PTR record or it is listed in RBL (Real-time block list), Sender’s MX record is missing, Sender is sending a spam mail etc. When these issues are encountered, it might cause message delay or never delivered to the destination. Because in these cases, the destination mail server will either reject or slow down the mails.

Some of the possible solutions for resolving the error are as follows:
  • Telnet Test

    We can perform a telnet to Port 25 on the remote domain mail server, which will indicate the reason behind the error of message delayed.
    Steps are as follows:
    1. Go to Start and type cmd & enter
    2. Ping the server by typing ‘telnet 25’ where is the name of the SMTP server of the email provider and 25 is port number used by SMTP service. After entering the command, we will be connected to
    3. Specify the domain that is used for sending mail by typing the command HELO and we will get a reply ‘250 HELO pleased to meet you’.
    4. We can check sender’s email address by typing command: ‘MAIL FROM:’ and we will get a message ending with ‘250...Sender OK’.
    5. Now, we will check the recipient’s email address by typing command: ‘RCPT TO:’ and we will get message ‘250…Recipient OK’.
    6. We can write the content of mail by typing DATA and enter. A subject will be entered like ‘SUBJECT: [any related subject for the mail]’ and enter twice. Type the message ending with a single period (.) and enter. If there is an issue in sending the mail, the error message will be displayed such as message was delayed or message was queued.

  • Troubleshooting

    We can take help of Toolbox to resolve the error. We will open the Exchange Management Console. Select Toolbox and open Queue Viewer. We can check if there is an inbound message for an accepted domain and error like 400 4.4.7 Message delayed error.
  • Steps to perform troubleshooting the error are as follows:
    1. Click on the Edge server in the Result pane and select Properties
    2. Search for the Internal DNS Lookups tab.
    3. Select: All Available
    4. Select one NIC adapter for the internal network if you have multiple NIC adapters and click ‘Use network card DNS settings’. The IP addresses will populate with DNS Server IP addresses from the internal network card.
    5. Restart the transport service instead of reboot
    6. There are two options if you have only one network card. Options are either select ‘Use these DNS servers’ and then select the IP address of internal DNS server or add host file containing the Information related to DNS server.


    In the blog, we have discussed the common error that occurs when a user tries to send mail from the account connected to MS Exchange Server and it is not being delivered on time displaying Error 400 4.4.7 Message Delayed. Further, some instructions are given to check why the error occurred and few feasible solutions have been described.


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