Why is Exchange Mailbox Not Receiving Email from External IDs?

Microsoft has provided some of the best software products for organizational level data sharing. MS Exchange is one of the foremost applications Microsoft has developed with advance facilities and optimum management of data. Despite of it being popular world-wide, some issues with this emailing platform can create nuisance for users. One of the common issues with Exchange is often queried by users that why is Exchange mailbox not receiving email from IDs outside Exchange. This blog will discuss about reason behind such problem and will also let users know how to troubleshoot this problem.

Root Cause for the Issue & Primary Checks

While configuration some settings are required in order to receive the emails from internal and external email addresses on Exchange 2013 platform. If you have set the entire required settings well, and still experiencing this problem then probably the issue is with internal DNS.

Exchange 2013 server installed with minimal default settings works well with the internal emails. The internal exchange of emails is done successfully but external emails are not received. For this some random fixes can be done in order to receive the emails from external addresses as well.

Primary Check: As soon as such kind of issue is experienced users are suggested to check the transport logs which will give an idea what is exactly happening with the outside emails. These logs are available in C:\Program Files\Microsoft\Exchange Server\V15\TransportRoles\Logs\FrontEnd\ProtocolLog\SmtpReceive. These logs can be checked and if it infers that the emails are reaching to the mail server but are excluded or blocked by the server then following settings can be done.

Troubleshooting Methods

Method 1: In order to rectify this issue, you can follow the below mentioned steps in order to change the DNS settings;

Change the settings of DNS and set local DNS server in external DNS lookups.
These settings are available under “Servers” where you can provide local DNS server IP for external DNS lookups.
After performing these settings restart MS Exchange transport along with front end transport service.
Method 2: Modification in the Host file can also help you to fix the issue. For this, open the Exchange server 2013 host file and enter the entries as mentioned below;

10.10.10.100   mailserver

10.10.10.100   mailserver.domainname.com

This method is a hit-or-miss method and works only in some cases.

Conclusion

If these methods are not working for you and you have noticed that the internal emails are also not being received by the Exchange mailbox, then there are chances that the mailbox has been corrupted. In such situation you can go for some better solutions to save the mailbox emails from being lost permanently. Some professional utilities like Exchange Server EDB File Recovery are available online which is capable to recover the email data to Outlook PST format. This application will recover the mailbox emails to PST recovering the data from it which can help you to avoid data loss.