> ## Documentation Index
> Fetch the complete documentation index at: https://moengage.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Why Does the SMTP Data Error Occur in Email Campaigns Sent Through Amazon SES?

> Troubleshoot SMTPDataError failures in MoEngage emails sent via Amazon SES, typically caused by exceeding daily sending quotas or rate limits.

## Problem

Emails could not be sent through Amazon Simple Email Service (Amazon SES) due to a "SMTPDataError."

## Explanation

* This error occurs when the Simple Mail Transfer Protocol (SMTP) connection is not correctly established for sending emails.
* Amazon SES imposes sending limits to control the number of emails that can be sent within 24 hours (daily sending quota) and per second.
* Suppose the number of messages exceeds the daily maximum for your AWS account. In that case, the API call made from MoEngage to Amazon SES will be rejected, resulting in a "454 Throttling failures: Daily message quota exceeded error(SMPTDataError)".

## Solution

To avoid this error during bulk email sending, consider the following points in coordination with the customer or Amazon support team:

* **IP usage**\
  Verify if the customer uses Amazon's dedicated or shared IPs.
  * *Dedicated IP.* The request limit is 40 emails per second for each IP. For example, if the customer uses three dedicated IPs, the limit would be 120 emails per second.
  * *Shared IPs.* The request limit is 500 emails per second, but the domain reputation might decline if multiple Amazon customers use the same IP.
* **Throttling settings**\
  Adjust throttling at the global level and campaign-level delivery control. For example, to target 55L users in a one-time Email campaign, it is recommended to use ten dedicated or shared IPs and set throttling to 20000 emails per minute in global and campaign settings.
* **Daily email request limit**\
  Confirm the total email request limit per day in the customer's Amazon account.

For more information, refer to:

* [Errors related to the sending quotas for your Amazon Simple Email Service (SES)](https://docs.aws.amazon.com/ses/latest/dg/manage-sending-quotas-errors.html).
* [What is Amazon SES?](https://docs.aws.amazon.com/ses/latest/dg/Welcome.html)