Webhook Delivery Errors — Troubleshooting Failed HTTP Callbacks

Fix webhook delivery failures including timeout errors, SSL issues, and retry handling for reliable event-driven HTTP callback integrations. This guide covers everything you need to know about this topic, including common causes, step-by-step solutions, and answers to frequently asked questions.

Here are the key things to understand: Webhooks are HTTP POST callbacks triggered by events in a source system. Delivery failures occur when the receiving endpoint is unreachable, slow, or returns non-2xx status. Most webhook providers implement exponential backoff retry strategies. Failed webhooks can cause data synchronization gaps between systems. Payload signature verification failures are a common cause of rejected webhooks. Understanding these fundamentals will help you diagnose and resolve this issue more effectively.

The most common reasons this occurs include: Receiving endpoint returning 5xx errors or timing out beyond the provider's limit (typically 5-30 seconds). SSL certificate errors on the receiving endpoint preventing HTTPS connections. Firewall or WAF blocking incoming webhook POST requests from provider IP ranges. Payload signature verification mismatch due to incorrect webhook secret configuration. Identifying the root cause is the first step toward finding the right solution.

To resolve this, follow these recommended steps: Check your endpoint logs for incoming requests — if none appear, the issue is network-level (firewall/DNS). Verify SSL certificate validity on your endpoint using 'openssl s_client -connect yourdomain.com:443'. Ensure your endpoint responds within the provider's timeout limit — offload processing to a background queue. Whitelist the webhook provider's IP ranges in your firewall and WAF rules. Verify the webhook secret matches between provider settings and your verification code. If these steps do not resolve the issue, consider consulting additional resources or a qualified professional.

This article is part of our HTTP Status Codes collection on Error Codes Wiki. We provide comprehensive, up-to-date information to help you find solutions quickly.