This topic is able to help you mend email problems which are associated with error code 550 4.4.7 if you see this at a non-delivery report (NDR). Mail flow problems can be frustrating, but we’ve got solutions you can try to do to be able to receive your message sent.

There may be several causes of dsn error code 4.4.7, so use the information in the NDR to choose how to repair the issue. For more details about the causes, see Causes for 4.4.7, after in this topic.

Message delivery from server-to-server can be challenging or require special access to settings, so most of these steps are designed for an Office 365 email administrator rather than the ordinary email sender. If the steps here do not help, contact your email administrator and refer them to this information so that they can attempt to resolve the issue for you.

If you obtain DSN error code 4.4.7 and also have problems sending email to recipients in 1 domain name only, the issue is probably with this particular destination domain name. A domain name is similar to a business name or the title of an email supplier and within an email address it shows on the side of the at symbol (@). By way of instance, in is your domain name. Find out more about domains in What are domain names? Possible causes of domain issues include:

  • Temporary community or Internet connection issues in the destination domain name.
  • Aggressive anti-spam settings in the destination domain which obstruct legitimate senders, as an instance, all senders from any domain in Exchange Online.
  • If you suspect the issue is using the destination domain name, allow the administrators of the domain understand. You Have to Offer the following information, which is comprised in the NDR:
  • The title of the email server at the destination domain name, along with also the error message returned from the email server.
  • The amount of delivery attempts made from the email server, an Exchange Online source server, and how long it attempted to get to the distant server.
  • The administrators at the destination domain will have to investigate what’s happening. Possible solutions might include:
  • Stop blocking messages from Exchange Online, or specifically allow messages from senders on your own domain name.
  • Contact the support channels due to their email server software or their hosted email service. Office 365 support might also be able to provide help.

If the steps in the email user aid section do not solve the issue for the sender, the solution may be associated with the method by which in which the user’s Office 365 domain is set up. If you’ve got a hybrid topology, the solution may also be associated with this on-premises configuration. Here are five solutions you may try. You may not have to try out all these to find the message sent successfully.

  • Solution 1: The email exchange (MX) record for your domain name might be missing or wrong. Get additional information about how MX records work inside the domain name system (DNS) in DNS basics.
  • Solution 2: You are able to test your MX record along with your ability to send email out of your company by using this Verify MX Record and Outbound Connector Test in Office 365 > Mail Flow Configuration from the Microsoft Remote Connectivity Analyzer.
  • Solution 3: The Sender Policy Framework (SPF) record for your domain name might be faulty , and may not include all sources of email on your domain.
  • Solution 4: Your domain name may have expired as a result of non-payment. Verify with your domain name registrar your domain is active and never expired.
  • Solution 5: Hybrid setup configuration issues. If your domain is part of a hybrid vehicle setup between Exchange and Exchange Online, and the recipient is at the on-premises business, there might be a issue with the hybrid configuration. Provide the information in the NDR for your on-premises Exchange administrators. They might have to run the Hybrid Configuration Wizard again because of changes in the on-premises IP addresses or firewall rules.

When Exchange Online attempts to send a message, the email server which generated the error may be unable or reluctant to take the message. This could result in a 4.x.x code being sent back again. A 4.x. The server doesn’t deny the message using a 5. X.x permanent error code, so the recipient doesn’t instantly get an NDR. Instead, Exchange Online repeatedly tries to send the message within two days. Just after two days of unsuccessful delivery attempts does the recipient get this NDR.

  • The server will not accept delivery of this message.
  • A system problem is causing delivery of this message into time-out.
  • The Exchange Online non-delivery report (NDR) notification for this specific mistake may comprise some or All the following information:
  • User information section
  • The server has attempted to provide this message, without success, and has stopped trying. If the issue continues, contact your helpdesk.
  • 450 4.7.0 Proxy session setup failed Frontend using ‘451 4.4.0 Primary target IP address responded with … make sure to list the mistake which follows this string as well as the last end point tried.

For more information you can visit:

Leave a Reply

Your email address will not be published. Required fields are marked *