Webhooks allow you to receive real-time notifications. For every developer, it is a kind of cool stuff unless it appears with webhook 503 service unavailable error.

Quite often, the same error pops up while using the applications in real servers.

That’s why at Bobcares we periodically get requests to solve such Webhook errors as a part of our Server Management Services.

Today, let’s analyze the causes and see how our Support Team fix Webhook errors for our customers.

What is a Webhook?

Webhooks are calls from one server to another. To clarify, on some specific events, it will trigger a call.
For example, say we have two abc.com and xyz.com. Meanwhile, if you signup on abc.com, it will send a request to xyz.com. Site xyz.com may use the call to send an email or something like that.

In real life, many popular applications use Webhooks. One classic example is Stripe payment solution. It has a webhook that will automatically send an email to a customer whenever a payment fails to go through.

Cause and Fix for webhook 503 service unavailable error

The error is more like a general server error rather than with the app. To clarify, the 503 error occurs mainly due to an unresponsive backend server.

All events include some information that we need to process and respond to it. For instance, let’s take the example of a messenger bot. Messenger platform will notify our bot via webhook event. Events trigger when any customer sends a message to our business page. Meanwhile, we need to process the information and respond to the event. So as a response our bot will reply with an automated message to the customer based on the query.

In case our server where the bot is present is down, the event will return 503 error as below :

{
"code": 143,
"error": "Invalid webhook response status: 503 Service Unavailable"
}

We’ll see the possible causes and how our Support Team fixed it.

1. Server Connectivity Issue

While it may sound simple, it simply indicates that the server somewhere in the chain is down or unreachable for whatever reason. It may return error as below :

Most modern Application does not reside on a single server. In other words, it is spread over multiple servers. Moreover, it may rely on any other 3rd party services too.

We start checking through all the workflows. The real challenge lies in finding the error source. We then fix the error causing the server unreachable. The common reasons include server firewall blocks, network errors, etc.

2. Host down

In many cases, the host of the application may be down. As a result, the error may happen.

We properly reboot all the systems. We also make sure that the webserver is up and running.

3. Application code or script bug

Additionally, some custom code within the application may also cause the 503 service unavailable error.

We usually dig the root cause or the file or code causing the problem. After that, we inform our client to consult the developer to fix the code.

[Having trouble in fixing webhook errors? – We’ll fix it for you.]

Conclusion

In short, the webhook 503 service unavailable error happens mainly because of server-side issues. Today, we saw how our Support Engineers fix errors related to webhooks.