Fixed: Email deferred due to greylisting

Is your email deferred due to greylisting? Our Support Engineers have not one, but three ways to resolve this troublesome issue.

Emails are often deferred when the server they are sent from is not on the Trusted Hosts list. It can also be due to not enabling Greylisting in WHM. With our Support Team by your side, track down the reason behind the issue and resolve it in no time.

What is Greylisting?

Greylisting occurs when your emails from unknown senders are deferred by the server. The server returns a message in response to the unknown email essentially stating that the server is busy and to try again later. If your emails are being deferred due to greylisting, don’t worry. Our Support Engineers have a couple of solutions up their sleeves.

WHM: Email deferred due to Greylisting

WHM, also known as WebHost Manager is a web-based control panel that is used for server administration. It is a very handy tool that helps you manage your entire server, create accounts, check systems, install and maintain software, assign features, track the usage of resources on the server, and so on.

However, sometimes you may come across the following when you navigate to Mail Delivery Reports in WHM and check the Results column of an email from a remote mail server:

Deferred due to greylisting. 
Host: 'RemoteServerIP' 
From: 'remoteemail@remotedomain.tld' 
To: 'localemail@localdomain.tld' 
SPF: 'unchecked'

This occurs due to either of the following three reasons:

1. Greylisting is enabled in WHM.
2. The Bypass Greylisting for Hosts with Valid SPF records option is not enabled.
3. The remote server is not on the list of Trusted Hosts.

Troubleshooting: Email deferred due to Greylisting

Troubleshooting tip 1:
The first option would be to check whether Greylisting is enabled or not. Navigate to Greylisting in WHM and if it is not enabled, do it. This will resolve your issue quickly.

Troubleshooting tip 2:
This solution comes in handy if the remote domain has a valid SPF record. You need to navigate to Bypass Greylisting for Hosts with Valid SPF Records in the WHM and enable it.

Troubleshooting tip 3:
The last solution is to add the IP address of the remote mail server to the Trusted Hosts list in the WHM. You will have to navigate to Trusted Hosts under Greylisting section in the WHM to do this. Additionally, you can also add the remote mail server’s IP address by going to the Report section under Greylisting in the WHM and clicking the “+” icon, and choosing the IP address to be added to the Trusted Hosts list.

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Conclusion

In brief, the Support Engineers offered us three different ways to resolve our email deferment issue due to Greylisting. This made it easy to ensure that the emails do not get deferred even if they arrive from a remote mail server.