Why did I get an email from AWS stating that my Amazon SNS subscription was manually disabled?

Last updated: 2021-11-18

I received an email from AWS saying that one of my Amazon Simple Notification Service (Amazon SNS) email subscriptions was manually disabled. Why was my Amazon SNS topic subscription deactivated, and how do I resolve the issue?

Short description

If messages are published to an SNS topic at a higher rate than the Delivery rate for email messages quota, then Amazon SNS deactivates the subscription.

Amazon SNS automatically deactivates subscriptions when TPS quotas are breached to do the following:

  • Prevent spamming the destination inbox with events.
  • Protect the recipient mail server from being flooded with messages.
  • Avoid Internet Service Providers (ISPs) identifying elevated traffic as spam and blocking messages from delivery.

Note: Amazon SNS supports an email message delivery rate of 10 transactions per second (TPS) to SNS topics, for each AWS account. For more information, see Amazon SNS endpoints and quotas.

Resolution

It's a best practice to avoid subscribing email addresses to high-volume SNS topics. Common use cases for SNS topic email subscriptions include monitoring Amazon CloudWatch alarms and sending usage reports to multiple email addresses.

For high-volume SNS topics, it's a best practice to subscribe only high-throughput, system-to-system endpoints instead. For example: Amazon Simple Queue Service (Amazon SQS) queues, AWS Lambda functions, and HTTP endpoints. These types of subscription endpoints support a higher TPS quota.