Error SMTP (550): failed to add recipient (No such recipient here)

When you try to send an email, this error usually occurs because the email address does not exist in the remote server.

How can I resolve this?

You cannot resolve this issue unless you are using our servers to host the recipient's email service or you have access to the email and DNS servers of the recipient's domain.

Why is this happening?

So far, we have identified three possibilities.

Possibility 1

Did you type the recipient's email address correctly? If yes, the person you are trying to contact may have given you the wrong email address. We suggest that you contact the user in another way.

Possibility 2

If the domain of the recipient's email address is hosted on the same server while it's using an external mail server or provider, it is necessary to configure the server to not handle the e-mails on the same server. On servers with a web control panel, such as cPanel or DirectAdmin, it is as easy as changing an option.

Possibility 3

If you are certain the recipient's email address is correct, you can try to use a third-party tool to test the reception of emails in the recipient's email address: https://testconnectivity.microsoft.com/tests/O365InboundSmtp/input

Kindly note, in the field of that webpage, you must enter the recipient's email address.

If the result is negative (showing at least one error): You will not be able to solve the issue on your side because it is a technical difficulty on the remote server. If this is the case, you can move forward to the following possibility available in this article.

If the result is positive (showing no errors): If the website of the recipient's domain is hosted on the same server you are using to send your email, and the email service is hosted by a third-party, make sure to unselect the option use the server to handle or receive emails.

If that option is already unselected or disabled, check the MX entries on the DNS servers in the test result.

If there are multiple MX entries on the DNS servers, associated with different email services, it may be possible that the email service for that domain is hosted on different email services. What is likely to be happening is that the email address is not associated with one of these email servers.

In the particular case of this test, the email was sent to the correct email server. Basically, this type of situation will cause intermittent sending failures which you do not have any control over.

In these types of situations, you may be able to send emails via the same email service where the domain is hosted. For example, if the domain is using Microsoft's email service, it may be possible to send emails from a Microsoft email service successfully. The tool provided by Microsoft to test the reception of email may show a positive result in this case as well. 

If there are no multiple MX entries on the DNS servers, it is possible that changes to the domain have occurred recently. If so, we suggest that you wait between 24 to 48 hours before trying to send your email again.

Regardless of the case, it is a technical difficulty related to the recipient's domain. On your side, there is nothing you can do unless you are using our servers to host the recipient's email service or have access to the email and DNS servers of the recipient's domain.

Possibility 4

If you are using our servers to host the recipient's email service, your domain and server must be configured correctly to be able to receive emails. Moreover, the email address must exist, obviously. If you are using our servers to host the recipient's email service, contact us for additional information and assistance.

If the recipient's domain is using a third-party service to host the email, contact the company providing this service so they can provide technical support and fix the issue.

Conclusion

The possibilities mentioned in this article are the most common ones. If you still require assistance, please contact us.