How to Troubleshoot Mail Flow Issues in Exchange Server?

Summary: You may face a situation where the users are not able to send or receive emails in Exchange Server. In this post, we’ll look at the reasons for the mail flow issue and the ways to resolve it. We’ll also mention an EDB converter tool that you can use to export mailboxes to a live Exchange Server, if the issue occurs after the migration.

If all the users are complaining that no emails are received or sent, it is a nightmare for any Exchange Server administrator. This can affect the entire communication and also the business of an organization. Therefore, the administrator has to quickly resolve the issue to bring the mail flow back. In this post, we will be discussing how to troubleshoot mail flow issues in Exchange Server – from 2007 till 2019.

What triggers mail flow issues?

The first thing to do is find out the reasons for such an issue. You can check what has changed in the current server setup. The best idea is to always keep a log of who had and what was changed. This way, if there would be a configuration issue, it?s easy to trace back and roll back any changes to identify the issue. Mail flow issue can be triggered after migration to a newer Exchange Server or due to a problem during an update of Exchange Server after installing a Cumulative Update (CU).

Troubleshooting Process

Let?s start by checking the queue of the Exchange Server to know if there are any issues with some emails that would be blocking the delivery of emails. This can be done by using the Get-Queue command in the Exchange Management Shell (EMS).

This will give a clear indication if the emails are delivered, being processed, or processing is stopped.

Make sure that the services of Exchange Server, set as automatic, are all running and started from the Services.

External factors would include network changes. Verify with the network team, if there were any changes in the port blocking the business routers or any changes in the perimeter firewalls. Next, confirm with the Server Administrators that there were no changes in the Windows Firewall rules.

You can check the internet domain MX records and others. You can also check if the external IP address of the Exchange Server is blacklisted.

Exchange Server email delivery is based on the send and receive connectors. You must ensure that these are working fine.

Open the Exchange Admin Center (EAC) and log in with your Exchange Administrator account.

Click on Mail Flow.

Here, you will see most of the factors that would affect email delivery.

In the Rules, check if there are any new rules that have affected the delivery.

Make sure that the domains used are listed and no errors are showing in the Accepted Domains.

In the receive connectors (incoming emails), you can check that there are no new connectors or new configurations that might be the culprit in the email delivery issue. You can disable the connectors, leaving only the bare minimum to ensure and test accordingly.

Same thing applied for issues with outgoing emails. Check the send connectors.

You can also launch the Exchange Remote Connectivity Analyzer Tool. This can be used from the Microsoft site. This is a web tool that is used to check inbound and outbound emails. This can confirm connectivity from outside your network and provide a better understanding of the problem.

How to Troubleshoot Mail Flow Issues in Exchange Server: The Conclusion

In events where there is a problem with the Exchange Server installation after migration or Cumulative Update (CU) or the Exchange Server is not responding or not receiving any emails, you can take the help of Stellar Converter for EDB. You can create a new Exchange Server and with this application, you can export everything to the new server with no hassle and no data loss.

Unlike the native tools, Stellar Converter for EDB can open multiple EDB files from any Exchange Server version without the need of a working Exchange Server. It can granularly export user mailboxes, shared mailboxes, archives, disabled mailboxes, and public folders to PST and other formats, such as EML, MSG, HTML, and PDF with no item or size limit. You can browse through the EDB files with a rich Outlook-like interface where you can preview items and see the whole structure of the mailboxes, including calendar, contacts, journal, and tasks.

Stellar Converter for EDB can export directly to another live Exchange Server or database to simplify the recovery even more. The application comes with value-added features, such as automatic or manual mailbox matching, parallel export, and continuation of the migration process if the application is interrupted.

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