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 2010 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.
The Conclusion
In events where there is a problem with the Exchange Server installation after migration or Cumulative Update (CU), or if the Exchange Server is not responding or receiving any emails, you can rely on Stellar Migrator for Exchange. You can set up a new Exchange Server and effortlessly migrate all mailboxes, public folders, and other data using this powerful application ensuring zero downtime and no data loss.
Unlike native tools, Stellar Migrator for Exchange supports seamless migration between any Exchange Server versions and even between Exchange and Office 365. It allows granular migration of user mailboxes, shared mailboxes, archives, and public folders, without any size limitations. You can easily map and migrate mailboxes through an intuitive interface with advanced features such as automatic mailbox matching, parallel migration, and resume migration if the process is interrupted.
The tool ensures smooth, secure, and efficient migration, making it an ideal choice for Exchange administrators looking for a reliable post-migration or upgrade solution.
