How do I troubleshoot email delays from greylisting for my Amazon SES email delivery?

Short description

When you use Amazon SES to send emails, you might encounter delays with emails being sent to specific recipients after emails leave SES. These delays can last up to 12 hours, and can be caused by an internet service provider (ISP) that "graylists" Amazon SES emails. Because the email comes from an unknown IP address and unknown email address, the ISP delays the email. Amazon SES receives a soft bounce and retries to send the email multiple times.

Resolution

To resolve greylisting delays, complete the following tasks.

Contact the recipient's ISP

If you notice persistent delays with a specific recipient, then contact the recipient's ISP or email administrator. Provide the ISP or administrator with the details of the delayed email. These details include the sender's email address, recipient's email address, and the time of the initial send. To resolve these issues, add Amazon SES to the allowlist of the ISP to bypass greylisting. For more information, see the Scenario 2: Emails are delayed inside SES section of Three places where your email could get delayed when sending through SES.

For dedicated IPs, review the reputation of the sending IP address

If your dedicated IP address is frequently greylisted, then review the reputation of the sending IP address. To give the ISP time to recognize the IP address, gradually increase the usage of your IP address.

If you are using Shared IPs, then you can use a dedicated IP address instead to better control your IP reputation.

Monitor your delivery performance

To monitor Amazon SES sending activity, you can use the SES console, APIs, or event publishing. When emails are greylisted, you can monitor the soft bounces. Set an event publishing to monitor all the soft bounce emails. Then, take action based on the error code that's included in the delayed email. For more information, see Amazon SES Delivery problems.

Contact AWS Support

If you're not sure if your emails are being greylisted, then contact AWS Support. Include the SES message ID in your communications with AWS Support.

Related information

Best practices for sending email using Amazon SES

Monitoring your Amazon SES sending activity

Understanding email deliverability in Amazon SES