如何调试我的SNS订阅？非AWS服务器HTTP/HTTPS端点问题排查

Hey Mike, let's figure out why your SNS topic isn't triggering that email from your endpoint. Since hitting the endpoint directly in your browser works, we know the endpoint itself is doing its job—so the problem's definitely in how SNS is communicating with it. Here's the step-by-step troubleshooting I'd recommend:

1. Double-Check Your SNS Subscription is Confirmed #

SNS requires explicit confirmation for HTTP/HTTPS endpoints before sending real messages. When you first added your endpoint as a subscriber, SNS sent a GET request containing a SubscribeURL parameter. You must visit that URL to confirm the subscription—otherwise, SNS will never deliver any messages to your endpoint.

• Head to the AWS Console > SNS > Subscriptions, and check the status of your endpoint. If it says PendingConfirmation, that's your fix: grab the SubscribeURL from the subscription details, open it in a browser, and complete the confirmation.

2. Inspect SNS Delivery Status & Errors #

Even if confirmed, SNS might be dropping messages due to delivery failures. You can dig into this easily from the AWS Console:

• Go to your SNS topic > Subscriptions > Select your endpoint > View "Delivery Status".
• Look for error codes like 4xx (client-side issues) or 5xx (server-side issues):
  • 403 Forbidden: Your endpoint's firewall or server might be blocking AWS SNS IP ranges. You'll need to whitelist the official AWS SNS IP ranges for your specific region.
  • 400 Bad Request: By default, SNS sends a POST request with a JSON payload. Double-check that your endpoint accepts POST requests (even if you don't process the payload, just make sure it doesn't reject the request outright).
• You can also adjust the retry policy for the subscription—tweak timeouts, retry counts, or specify which status codes trigger retries in the subscription's "Delivery Policy" settings.

3. Use CloudWatch Logs to See Exact SNS Requests #

To get full visibility into what SNS is sending (and how your endpoint is responding), enable CloudWatch Logs for your SNS topic:

• Go to your SNS topic > Delivery Status Logs > Enable logging to a CloudWatch Log group.
• Trigger an SNS message, then check the CloudWatch logs. Compare the request details (headers, HTTP method, payload) to what your browser sends. Look for differences—like a missing header or unexpected HTTP method—that might be preventing your endpoint from triggering the email.

4. Validate SSL/TLS Settings (For HTTPS Endpoints) #

If your endpoint uses HTTPS, SNS requires a valid, publicly trusted SSL certificate (self-signed certs won't work unless you jump through extra hoops to configure SNS to accept them, which isn't recommended for production).

• Verify your certificate is issued by a public CA, hasn't expired, and matches your endpoint's domain.
• If you're using a CDN or WAF in front of your endpoint, make sure its SSL configuration is set up correctly (no mixed content issues, proper certificate forwarding).

5. Test with a Simplified Request #

By default, SNS sends POST requests with JSON payloads. Try matching what your browser does to narrow down the issue:

• In the AWS Console, create a test SNS message and send it to your endpoint.
• Temporarily reconfigure your subscription to use GET requests (the same method your browser uses) to see if that triggers the email. You can set the HTTP method in the subscription's "Protocol Details" settings.

6. Check Firewall/Network Restrictions #

Your non-AWS server might be blocking incoming requests from AWS:

• Ensure your server's firewall allows incoming traffic on port 80 (HTTP) or 443 (HTTPS) from AWS SNS IP ranges.
• If you're using a web application firewall (WAF), check its logs for blocked requests from AWS IP addresses—SNS requests might be getting flagged as malicious.

Once you work through these steps, you should be able to pinpoint exactly why SNS isn't triggering your email. If you find specific error codes or log entries that don't make sense, feel free to share them and I can help dig deeper!

内容的提问来源于stack exchange，提问作者Mike