A Fix for Server error: '550 5.7.1 Unable to relay'

An Exchange Administrator is always concerned with all the user data stored on the server and needs to take care of it. There are various situations that lead to loss of data on Exchange and throw various error messages. One of such messages is described in this post along with possible workarounds you can try out to allow your users get access to all the data and continue working with Outlook. Carry on.

Error

Server error: '550 5.7.1 Unable to relay'

Symptom

The error occurs when users try to send email messages to the addresses outside the domain of organization.

Cause of the Error

You may face the Mail Relay error due to the following causes:

• You generally face the error while getting connected to a mail server on one domain and try to send emails on an external domain using another server. The error occurs because the outgoing mail server cannot recognize you and therefore, does not allow sending emails.
•   Another reason may include no existence of a policy for expected domain in the organization.

Resolution

It must be on priority in your task list to fix the error as early as possible. Below steps will help you fix the problem, make certain that you perform the steps carefully:

•  Start ESM (Exchange System Manager), and then use SMTP virtual server that is being used for sending email messages. Once you are in virtual server, select 'Properties', select 'Access', and then select 'Relay'. Next, check whether the option 'Allow computers which successfully authenticate to relay' is enabled. If not, do it.
• You may also set maximum diagnostics logging on Queuing Engine, MSExchangeTransport, and Connection Manager for server that has the system, facing issues. Next, check the application event log for the errors, and if errors are found, resolve them by using relevant strategies.

However, you may find that the error has not been resolved with the above given resolution and you can be stuck with the same issue. Besides, your users will not be able to use Outlook properly. In this case, it is important to look for a solution that can fix the issue efficiently and effectively.

A commercial Exchange repair software program will help you get over the problem and provide expected results. However, it is important to have a competent and efficient software application that can provide greater results and fix all the errors permanently.