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Rectify the Exchange Server Error 550 5.7.1 Unable to Relay

Published By Nilesh Kumar
Debasish Pramanik
Approved By Debasish Pramanik
Published On January 25th, 2024
Reading Time 4 Minutes Reading

A networking protocol is used for mailing emails from an email application to the server or vice-versa with port number 25. This device is named as Simple mail transfer protocol, which is responsible for sending emails all around the world. However, sometimes an error statement occurs i.e. Exchange Server Error 550 5.7.1 Unable to Relay. Such interruption stops one from sending emails to the recipients and hence, pause the ongoing work.

This error 550 denotes that the recipient’s email address is not authentic on the server and hence, failed to send a message. Another cause for this problem might be the nonexistence of a targeted Recipient’s policy on a specific domain in the network of the sender. Apart from these two, there is one major reason behind the existence of this problem i.e., corruption in the Exchange database file.

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Description of the SMTP Error Code

In some conditions, the HTTP protocol gives back a mysterious code of the error and make users unable to send the message. One should not ignore this message code because it have some important information regarding the reason behind the occurrence of this error message. This code comprises of three-digits where per digit is having its own identity.

The starting digit indicates whether the server had encounter error, accepted the command, or had started with appropriate action. This digit is pointed by any of the 5 different values:

a) Digit 1 denotes that command is successfully accepted by the server but, none of the action is taken and a message for confirmation is still awaited.
b) Digit 2 denotes that the action is successfully finished
c) Digit 3 states that the Exchange server is able to understand the action but, the description is needed for its completion.
d) Digit 4 states that a sudden failure had occurred in between the procedure therefore, you need to re-execute the procedure without any changes.
e) Digit 5 indicates that the server has been prone to some major problem.

If there is any syntax error or network problem then, a subsequent code will also appear. This code is appeared in any of the following six digit:

a) Digit 1 denotes that there is some syntax error
b) Digit 2 denotes some kind of informational response
c) Digit 3 denotes the current status of connection
d) Digit 4 and 5 are reasons, which are not yet specified
e) Digit 6 gives the report of mailing system as of a whole

For security purpose, the Exchange server shows a security-based error message, if it is preventing the server from any hazardous issue. Fix error 550 5.7.1 Unable to Relay in Exchange 2016, 2013, etc.

First of all, one should give a try to manual solution for troubleshooting the issue.

Strategy to Fix the Error 550 5.7.1 Unable to Relay is described below:

1. Launch Exchange server manager application
2. Click on Administrative Groups >> Administrative Group Names >> choose the server and then, its name
3. Hit on Protocols and select SMTP option from it
4. Right-click on the Default SMTP Virtual server and choose Properties option from it
5. Go to Access tab and click on Relay >> only the list below option
6. Choose IP that you…. and then enable the checkbox of Allow all computers…
7. Close the opened tabs and try to send the message

If the message is sent successfully then, no need for going to any opt solution. But, if something still went wrong then, it means that the major cause of the problem is corruption in the Exchange database file.

Well, this can be fixed by the Exmerge utility but, this solution requires high-level knowledge of the server and also a technical expert to accomplish task. User can use the third-party tool mentioned here, that easily recover major corruption from offline/dismounted EDB file.

However, there is one more problem with this workaround that if something went wrong while implementing the procedure then, there are chances of other applications being getting affected.

Observational Verdict

How to troubleshoot error 550 5.7.1 Unable to Relay becomes a big issue for end-users when they are not able to fix the problem by enabling SMTP protocol. Therefore, a recommended approach is to opt for a third-party tool where users will just have to browse corrupt Exchange database files in EDB recovery software and then, within just a few minutes they will be having a healthy file without any hassle.


By Nilesh Kumar

As a Chief Technical Writer, I know the technical issues faced by home and professional users. So, I decided to share all my knowledge via this blog. I love to help you with challenges while dealing with technical jargon.