AWS SNS

Overview

The AWS SNS Connector allows you to send SMS messages using Amazon Simple Notification Service (SNS). However, there are certain limitations and prerequisites that must be met for successful message delivery.

Prerequisites

Before using the AWS SNS Connector to send SMS messages, ensure the following:

1. SNS Sandbox Registration:

   • If your AWS account is in SNS SMS Sandbox Mode, SMS messages can only be sent to verified phone numbers added in the AWS Console.

   • To register a phone number, follow AWS documentation.

2. Region Compatibility:

   • The SNS SMS service may be region-dependent. Ensure the selected region supports SNS SMS services.

   • Messages might only be delivered if the selected region matches your AWS account’s region.

3. Spending Limit:

   • AWS imposes a default spending limit of $1 USD for SMS.

   • If the limit is reached, no SMS will be sent.

   • Check and increase the limit in the AWS SNS console under SMS settings.

4. IAM Permissions:

   • To enable SMS delivery logs, you must have the necessary IAM permissions.

   • Without proper permissions, viewing SMS failures or debugging will not be possible.

   • Check IAM policies and request permissions if needed.

Important Considerations

✅ 200 OK Response Does Not Guarantee SMS Delivery

• When an SMS is published via SNS, a 200 OK response is returned.

• However, this only confirms that SNS received the request. It does not confirm message delivery.

• To track the status of an SMS:

  • Enable CloudWatch Logs for SNS SMS (requires permissions).

  • Use AWS SNS Delivery Status Logs to check failures.

✅ Common Issues and Solutions

Issue	Cause	Solution
SMS not received	Phone number not verified in sandbox	Add number to SNS sandbox
200 OK but no SMS	No balance in the AWS SNS SMS spend limit	Increase spending limit in AWS console
SMS delivery failure	Region mismatch	Use the correct region for SMS service
Unable to view logs	Insufficient IAM permissions	Request permissions to enable CloudWatch logs

Debugging Steps

1. Verify Phone Number:

   • Check if the recipient's number is added in the AWS SNS SMS sandbox.

2. Check Spend Limit:

   • Go to AWS SNS Console → Text Messaging (SMS) → Spend Limit.

3. Enable Logs for Debugging:

   • Navigate to AWS CloudWatch Logs and enable SNS delivery status logs.

   • Ensure IAM permissions allow access to logs.

4. Confirm Region Settings:

   • Use a region that supports SNS SMS delivery.

References

• Publishing SMS messages to a mobile phone using Amazon SNS

• Adding and verifying phone numbers in the Amazon SNS SMS sandbox

• Troubleshooting AWS SNS SMS Issues

Conclusion

The AWS SNS Connector itself functions correctly. However, message delivery depends on AWS account settings, sandbox verification, spending limits, region settings, and logging permissions. By following the prerequisites and debugging steps above, users can ensure successful SMS delivery through AWS SNS.

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For further assistance, consult AWS support or refer to the official SNS documentation.