Introduction to Amazon SNS Troubleshooting
Amazon Simple Notification Service (SNS) is a fully managed pub/sub messaging service that enables decoupled communication between microservices, distributed systems, and serverless applications. While SNS is highly reliable at scale, developers frequently encounter subtle configuration and integration issues that can silently break message delivery. This tutorial walks through the most common SNS problems, their root causes, and actionable solutions with code examples.
Why SNS Troubleshooting Matters
Because SNS is often positioned at the center of event-driven architectures, a single misconfiguration can cascade into failed notifications, dropped events, and broken business workflows. Worse, SNS is designed to be "fire and forget" — when delivery fails, the service may silently retry or drop messages without obvious application-level errors. Understanding how to diagnose and resolve these issues is essential for building resilient AWS architectures.
Common Issue 1: Messages Not Reaching Subscribers
The most frequent SNS complaint is that messages are published successfully but never arrive at the subscriber endpoint. This typically stems from one of three causes: subscription status is not confirmed, the subscription filter policy is excluding the message, or the endpoint's access policy is blocking SNS.
Checking Subscription Status
Every SNS subscription (except SQS and Lambda) requires explicit confirmation. If the subscription remains in PendingConfirmation status, no messages will be delivered. Use the AWS CLI to inspect subscriptions:
aws sns list-subscriptions-by-topic \
--topic-arn arn:aws:sns:us-east-1:123456789012:my-topic
# Output will show SubscriptionArn as "PendingConfirmation" if unconfirmed
To programmatically confirm a subscription, the endpoint owner must visit the confirmation URL sent by AWS. For automated workflows, you can capture the token and call confirm-subscription:
aws sns confirm-subscription \
--topic-arn arn:aws:sns:us-east-1:123456789012:my-topic \
--token "2336412f37fb687f5d51e6e241d59b34c4068c296a5f5c57e76c4b5b496e1c2f2dc6e8b5b3e5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b5b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