Exchange server uses Simple Mail Transfer Protocol (SMTP) to send emails from an email client to the server and vice versa. It is responsible for sending data over the network. In Exchange, after enabling the IMAP or POP3, you must configure the authenticated SMTP settings for users so that they can send emails.
Sometimes, the email delivery may fail and the following message may get relayed back to the server — an SMTP error code 550 5.7.1,
«The SMTP mail system returned the following error: (0x8004020F): The server rejected one or more of the recipient addresses. The server response was 550 5.7.1 Unable to relay»
In a nutshell, this message is a non-delivery report (NDR) or delivery status notification (DSN) of emails. The error 550 5.7.1 generally implies that the user is not authorized, and therefore, fails to send emails. As a result, the message is relayed back to the server.
What is SMTP Error 550 5.7.1 Unable to Relay?
The error ‘550 5.7.1 Unable to relay’ is a cryptic error code by HTTP protocol, which restricts users from sending emails. The error codes describe important information about the persisting problem. It usually consists of three digits where each digit defines a particular attribute. In such a situation, you need to fix the SMTP error 550 by understanding the meaning and reason for the occurrence. The description of the error 550 Unable to relay a message is as follows,
- The first digit describes whether the Exchange server accepts the command, encounters an error, or commences appropriate action.
- The subsequent digits display if any connection or syntax error exists. It can be considered as a security-specific error message if it prevents unauthorized users from gaining access to the Exchange server for relaying emails.
What Factors are Responsible for SMTP Error 550 5.7.1 ‘Unable to Relay’?
There could be various reasons responsible for the occurrence of Exchange SMTP error 550 Unable to relay error. These are:
- Authentication failure/don’t have permission to send messages to the recipient
- The sender address is not recognized by the Outgoing Mail Server
- Exchange database corruption
- The Recipient Policy of the recipient domain blocks the emails from the sender domain
- Email routed to the wrong server
- Sending an email to a large distribution group
Most commonly, the reason could be database corruption or the nonexistence of a specific Recipient’s policy for the particular domain in the user’s department in the Exchange server database(s) that results in this error message.
How to Fix Exchange SMTP Error 550 5.7.1 ‘Unable to Relay’?
Below we have provided a few manual solutions to fix Exchange Error 550 5.7.1. However, you may require considerable technical expertise to execute the steps. Hence, good know-how of the Exchange server processes is essential. You also need administrator access and permissions to execute the commands and steps discussed below.
Method 1: Check Event Logs
Check for all existing Exchange server errors in the application event log and search for corresponding resolution methods online. Checking the application event logs will help you analyze the actual cause and time when the ‘Exchange SMTP Error 550 5.7.1 unable to relay’ error message is generated.
Method 2: Contact Recipient or Recipient’s Email Admin
As mentioned earlier, if the sender’s address is not recognized by the Outgoing Mail Server, the email delivery may fail. In such a case, you may contact the recipient or recipient’s email admin to fix the problem from their end. Tell the admin or the recipient about the email delivery problem and ask them to reconfigure the recipient’s mailbox. This may help you stop the SMTP error 550.
Method 3: Use Exchange Server Manager
You can use the Exchange Server Manager to fix the failed email delivery issue and the Exchange SMTP error 550 5.7.1 Unable to relay. The steps are as follows:
- Start Exchange Server Manager
- Go to Administrative Groups in the Exchange Server Manager
- SelectAdministrative Group Name, select Server, and then the Server Name
- Next, click on Protocols and select SMTP
- Then right-click Default SMTP Virtual Server to select Properties
- Click on the Access tab and then click on Relay to select only the list below
- Next, select the IP that you want to relay and the domain
- Finally, check the box associated with «Allow all computers which successfully authenticate to relay regardless of the list above»
- Close all opened tabs. The SMTP Server now enables you to send emails
Method 4: Use EseUtil
Sometimes, the SMTP error 550 5.7.1 may also occur due to a problem with the Exchange database file (EDB). Common factors, such as virus or malware intrusion, power failure, force shutdown, incompatible antivirus software, or server crash, may cause database corruption that can lead to the ‘Exchange SMTP Error 550 Unable to Relay’ error. To fix database corruption, you can use the EseUtil, an Exchange built-in utility offered by Microsoft. You can also use EseUtil, which is located at C:\Program Files\Microsoft\Exchange Server\Vxx\Bin, to check database integrity, defragment the database, and reduce the database size.
Following are some EseUtil commands that you can use to perform various operations on the Exchange database.
- Defragment Database
ESEUTIL /D
- Check Database Integrity
ESEUTIL /g < path to database file>
- Perform Soft Recovery
ESEUTL /P
In Exchange 2010 and earlier versions, you need to use the Isinteg as EseUtil is available in Exchange 2010 SP1 and later versions only.
Isinteg –s
- Perform Hard Recovery (May cause Data Loss)
ESEUTIL /C
TIP: Always dismount the database and create a backup copy of the database before performing any operation on the Exchange database file.
Method 5: Use an Exchange Recovery Software
The probabilities to resolve the error via EseUtil is based on the intensity of corruption in the EDB files and incorporated objects. Plus, it may cause permanent data loss, if hard recovery is performed. Thus, in case of severe corruption and to avoid data loss, it is always better to deploy a professional Exchange recovery software, such as Stellar Repair for Exchange.
The Exchange recovery software repairs corrupt and damaged Exchange database files, extract the mailboxes, and saves them as PST without any data loss. You may also import the extracted mailboxes and mailbox items to the live Exchange server directly by using the software. Plus, it also helps Exchange admins to recover and restore deleted mailboxes from Exchange 2019, 2016, 2013, 2010, 2007, 2003, 2002, 2000, and Exchange 5.5 database files in a few clicks.
Final Thoughts
The 550 5.7.1 Unable to relay SMTP error can be resolved by following the manual methods discussed in this guide. However, these methods work only if the reason for SMTP 5.7.1 error is due to authentication, recipient policy, and permission related problems. These methods won’t work if the problem is caused due to integrity issues with the Exchange database file.
In such cases, you may use EseUtil to repair the database via soft or hard repair commands. But EseUtil may cause data loss and fail to repair the database if the corruption is severe. To avoid data loss and restore mailboxes from a severely corrupt or damaged database, you can use an advanced Exchange recovery software, such as Stellar Repair for Exchange. This can help you quickly fix the problem with the Exchange database and avoid the Exchange SMTP error 550 5.7.1 Unable to relay error message.
Working with Exchange Server itself is a challenge!
With vast number of facilities in data management and exchange, there come responsibilities to handle multiple errors which can appear anytime in front of you. We are going to discuss one such common Exchange error – “Exchange SMTP Error 550 5.7.1 Unable to Relay” which is haunting the Exchange administrators for long. In this article, you will find some native approaches to fix the error while discussing about the nature and causes of this SMTP error in detail. Let us read this blog carefully.
What is Exchange SMTP Error 550 5.7.1 Unable to Relay? When and how it occurs?
Exchange SMTP Error 550 5.7.1 Unable to Relay usually indicates certain cryptic error codes by the HTTP Protocol meant to restrict emails from sending between Exchange Server and its client application. This message is basically a non-delivery report of emails relay by the Microsoft Exchange Server. This error occurs when the Exchange user or administrator is trying to send emails between Exchange client and server and the recipient has not enabled the relay feature. It restricts any email transfer between the server and client due to message relay and come up with an error message resembling delivery failure of emails. There is another chance of Exchange Server sending commercial emails along with remote domain sending unsolicited emails information while encountering this error.
The message display is as follows:
Error Message:
Undeliverable:abc
System Administrator
Your message did not reach some or all of the intended recipients.
The following recipient(s) could not be reached:
550 5.7.1 Unable to relay for abc12@x212.com
Common indications of the Exchange SMTP Error “Unable to Relay” are:
- Send/Receive failure of the emails displaying error code 5.7.1, 5.0.0 or 5.7.3
- With constant increase in domain counts, occurrence of error message
- Sending of commercial email messages through Exchange Server while remote domain will send unsolicited commercial emails information received through the Exchange system
The user should know the possible reasons behind this SMTP error to get back to the normal exchange of email messages between the Exchange Server and Client. Read out the causes for this troublesome SMTP error in the below-stated points.
- SMTP authentication failure for the respective sender domain
- Outgoing Mail Server fails to recognize the sender address
- Restrictions on sender domain defined by the receiver domain under Recipient’s policy
- Email message was routed to the incorrect email server
- Email sent to a big number of recipients or distribution group
- Exchange Server Database is corrupted
Learn Manual Fixes for Exchange SMTP Error 550 5.7.1 Unable to Relay
With the Exchange Server Manager, Exchange administrators can settle or fix this SMTP error as they can manually choose and assign the IP address and domain name which they want to relay from the default SMTP Virtual Server. It may help the sender domain authentication as well as in recognizing the sender address.
Please note that this manual approach is applicable for the Microsoft Exchange 2010 and above versions only.
Using Exchange Server Manager to Fix Exchange SMTP Error 550 5.7.1 Unable to Relay
Exchange administrators or users with assigned administrator rights need to perform the following steps in the given sequence to fix “Exchange SMTP Error 550 5.7.1 Unable to Relay issue”.
- Start your Exchange system (on which Exchange Server is installed) and launch the Exchange Server Manager on it.
- On the left panel of the page, go to the Administrative Groups section.
- Under the Administrative Groups section, navigate to the Administrative Group Name>>Server>>Server Name.
- Under your Server Name, click Protocols option and then select SMTP option.
- Now, right-click on the Default SMTP Virtual Server option and click on Properties option from the list.
- Next, click on the Access tab, click on the Relay option and choose Only The List Below option.
- Select the IP address and Domain name for relay purpose. Select the checkbox saying “Allow all the systems to successfully authenticate to relay regardless of the list above”. Click OK.
- Finally, closed all the opened tabs and Exchange Server Manager.
- Try to send the emails now and check if this SMTP Error is eliminated or not.
Note: Exchange administrators can also check the Exchange SMTP Error detail in the Application Event Log and perform the provided solution online from there. Or, can directly contact the recipient and inform him about the issue and seek solutions from their end.
The above approach can handle your issue of failure in email delivery. But, if the cause is something else and not the wrong authentication or restricted Recipient Policy, then you need to be more cautious here. If this solution does not get well for you, then remember one more reason for this error is mentioned at the start of this blog which is the corrupted Exchange Server database. Corruption in an Exchange database could be due to many factors such as virus infections, incorrect modifications in database schema, objects, intermittent power-supply, and sudden shutdown of system, interference of other installed programs like Firewalls or Anti-virus or more other factors. There could be many issues with a corrupted Exchange database which results in different errors one of which could be this Exchange SMTP Error 550 Unable to Relay. So, there is an utmost need to repair the corrupted Exchange database for normal functioning of the Exchange Server.
In-Built Repair Utility – Eseutil by Microsoft Exchange Server
Exchange Server has an in-built utility namely Eseutil for soft and hard Exchange database recovery, available at the Exchange system location
C:\Program Files\Microsoft\Exchange Server\V15\Bin
which can be used to defragment Exchange database, checking its integrity, repairing the corrupted database and also to reduce Exchange database size.
The basic command for repairing the corrupt Exchange database is – eseutil /p <location of the database>
Before running any command on the Eseutil application, it is strongly recommended to have a backup of your Exchange database file as manual way to repair Exchange database file can lead to loss of data during the repair process. One more drawback of this solution is this method is not suitable for large-sized Exchange database files as well as files with high intensity of corruptions. Also, users need to first dismount the Exchange database to run these commands on it and hence, it remains inaccessible at that time.
To deal with highly corrupted Exchange database files, we recommend you to opt for a reliable third-party tool. Exchange Server Recovery tool is an efficient tool with highly advanced programming and quite simple designed user-interface. It helps users to repair Exchange database with any sort of corruption level in few steps and fix different Exchange errors simultaneously. Users can choose the Exchange data owing to multiple smart filters and options integrated in the tool’s interface. The tool does not require much technical knowledge and can be run by all users because of the interactive user interface and features. The tool does not impose any restrictions on the Exchange Server rather support almost all versions of Exchange Server for complete data recovery and errors fixing. Before buying this tool, we advise you to know well about its features through its demo version available at the site.
Download Now
Read Related Blogs
- Methods to Export Disconnected Exchange User Mailbox to PST
- Free Methods to Convert Exchange EDB to PST File
- Cached Exchange Mode in Outlook & How to Enable or Disable?
- Exporting Exchange Server Public Folder to Outlook PST Secure Ways
- Quick Fix for Exchange Server is Unavailable Error
SMTP stands for Simple Mail Transfer Protocol that works to send emails between the server and its email clients. It works the same in the Exchange Server and is used for communication between the Exchange Server and its client. However, sometimes, you will face some issues like 550 5.7.1 error code displaying “Unable to relay” while trying to send emails through SMTP. Let us find out what is Exchange SMTP error 550 5.7.1 and then ways to fix this to get back emails accessibility hindered before.
What is Error SMTP error 550 5.7.1?
The SMTP error 550 5.7.1 occurs in In Exchange 2016, 2013, 2010, or 2007 versions while users trying to send emails. If Exchange finds that any unauthorized user is accessing the Exchange Server, then it will display SMTP error 550 5.7.1 with the error message “Unable to relay.”
This error can happen to any user and can block emails from being sent. This error consists of three-digit codes, and each digit has a meaning.
What are the causes of SMTP error 550 5.7.1?
There are some factors that are responsible for this error like:
- There is an unknown sender, or the Outgoing Mail Server does not recognize the sender.
- Sender domain fails to be authenticated
- The recipient policy of the receiver domain blocks emails from the sender domain.
How to fix 550 5.7.1 error unable to relay in Exchange Server
- Launch Exchange Server Manager and move to Administrative Groups.
- Select Administrative Group Name then choose Server>Server Name.
- Now click on Protocols and Select SMTP.
- Right-click on Default SMTP Virtual Server and select Properties
- In Access tab, click on Relay>only the list below
- Now check the checkbox “Allow all systems to successfully authenticate to relay regardless of the list above” and close.
Now you can send messages as normal.
What to do if you are not able to send messages because of EDB corruption?
Exchange Server Recovery software helps you in repairing your corrupted EDB files.
Sometimes users will find that mailboxes are inaccessible due to damaged EDB files. So, repair your EDB files with this fully automated tool. With this comprehensive Exchange Server Recovery tool, you can migrate your repaired EDB files to Live Exchange or Office 365. It has options to migrate mailboxes from Live Exchange to Office 365 and vice versa. The software works with all versions of MS Exchange Server and Windows OS, and all plans of Office 365.
Conclusion
Exchange SMTP error blocks sending and receiving emails from server to client due to unknown sender, incorrect authentication, or recipient policy based on which a manual solution via Exchange Server Manager is explained. Inability to access Exchange data can also occur due to corruption in the database file and so, a trusted professional Exchange Recovery tool is suggested for the Exchange users.
- Remove From My Forums
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Question
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Здравствуйте!
Я установил сервер Exchange 2019.
Почта внутри домена работает без проблем.
Пользователи могут легко получать сообщения, отправленные из Интернета.
Но интернет-сообщения не отправляются.
Соединитель отправки настраивается в соответствии с документацией https://docs.microsoft.com/en-us/exchange/mail-flow/connectors/internet-mail-send-connectors?view=exchserver-2019.
Но при отправке сообщения на внешний адрес через OWA выдается ошибка 550 550 5.7.54 SMTP;
Невозможно ретранслировать получателя в непринятом домене.
Соединение через порт 25 проходит (проверено через telnet.)
Сервер с ролью EDGE Transport не установлен.
Many thanks for the prompt replies. I solved the problem myself. Because of the incorrect settings, the external firewall nat differed in the packet paths, as a result of which no connection was established. Thanks again, the topic can be closed.
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Edited by
Saturday, January 26, 2019 11:07 PM
Solved
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Edited by
Answers
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please post the output of
get-sendconnector | fl
and
get-accepteddomain
MCSA exchange 2016 | MCTS exchange 2013 | MCTS-MCITP exchange 2010 | MCTS-MCITP Exchange: 2007 | MCSA Messaging: 2003 | MCP windows 2000
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Marked as answer by
777skiv777
Saturday, January 26, 2019 11:09 PM
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Marked as answer by
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Hi,
Generally, the error «550 550 5.7.54» indicates that the receive connector does not allow an anonymous or unauthenticated sender to relay to external address.
Please try to create a receive connector for anonymous relay and configure the permission for anonymous relay on the dedicated connector. You can run the following commands to configure anonymous relay.
New-ReceiveConnector -Name <ConnectorName> -TransportRole FrontendTransport -Custom -Bindings <LocalIPAddresses>:25 -RemoteIpRanges <RemoteIPAddresses> Set-ReceiveConnector "<ConnectorName>" -PermissionGroups AnonymousUsers Get-ReceiveConnector "<ConnectorName>" | Add-ADPermission -User "NT AUTHORITY\ANONYMOUS LOGON" -ExtendedRights "Ms-Exch-SMTP-Accept-Any-Recipient"
For your reference:
Allow anonymous relay on Exchange servers
Regards,
Dawn Zhou
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mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact
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Marked as answer by
777skiv777
Saturday, January 26, 2019 11:09 PM
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Marked as answer by
- Post author:Daniel Bradley
- Post category:Exchange Online / Microsoft 365 / Tutorials
If you have received a non-delivery report from Microsoft Outlook with error 550 5.4.1 (Recipient address rejected) it is likely you received this message shortly after sending an email to either someone you have already emailed in the past or someone you have just emailed for the first time.
What does error 550 5.4.1 mean?
Error 550 5.4.1 means that fundamentally, there is an issue on either the sending side of the email, the receiving side, or somewhere in the middle (with Microsoft). Where you see the information stating that the address has been rejected, this has been generated from the receiving server, so for what-ever reason, the organisation that is receiving your email, has rejected your email… this may be intentionally, accidentally or temporarily out of your control.
What can the sender do to help resolve this error?
There are a couple of options for you to work through to aid in resolving this issue and I will list them below.
- Just wait. In some instances, you may need to just wait and try again later in the day or the next day. In the instance there is a service outage or the email administrator has made some system changes, this could be the only option. I have detailed in another post how you can view the service health in Exchange Online, Troubleshoot Exchange Online server issues.
- Ensure your DNS records are correct. By this I mean specifically your SPF, DKIM and DMARC records which are there to verify you an authorised sender of your companies domain (ourcloudnetwork.com for example).
- Check your domain status in the Microsoft 365 admin center.
- Log in to the Microsoft 365 admin center
- From the left-hand menu, select domains and ensure the domain is listed as active
- Now go to Admin and select the Exchange admin center
- Click on Mail flow, then Accepted domains
- Confirm that your domain is listed and the domain type for the domain is set to Authoritative or internal relay.
What can the recipient can do to help resolve this error?
If you are an Exchange administrator and your staff has informed you that users are getting a 550 5.4.1 error when people are emailing them, then there are some steps you can take to ensure the issue is remediated on your side.
- Ensure the email address is valid. In some instances, the user may have provided the sender the wrong email address or the email address includes confusing characters such as a capital ‘i’ and lowercase ‘L’. You can use the message trace logs to verify this is the case. See my guide, How to Interpret message trace results and policies in Exchange Online.
- Review your Exchange Transport Rules. If the email address is valid, you may have received some more relevant information from the message trace results, as per the above link. In which, for the next steps you should look at your transport rules. There may likely be a rule which rejects the message based on certain criteria. This will also help the sender resolve any issues if you have taken security measures to reject emails which fail DMARC for example.
- Review your Hybrid Deployment. You may be running a hybrid deployment between on-premise Exchange or another solution. As such, you should review your send connectors and receive connectors for any problems. Follow my guide on How To Validate Connectors In Exchange Online To Resolve Mail Flow Issues.
Daniel Bradley
My name is Daniel Bradley and I work with Microsoft 365 and Azure as an Engineer and Consultant. I enjoy writing technical content for you and engaging with the community. All opinions are my own.