~3 min read • Updated Feb 21, 2026
1. Overview of HTTP Error Codes
HTTP status codes indicate the result of a visitor’s request to a URL. These three‑digit codes help diagnose issues related to client requests, server responses, and website configuration.
The five classes of HTTP codes include:
- 1xx, 2xx, 3xx — Successful or functional requests.
- 4xx — Client‑side errors.
- 5xx — Server‑side errors.
2. Common 4xx Client Errors
These errors occur due to issues with the client request, but they often indicate problems on the website itself.
2.1 400 — Bad Request
The request contains invalid syntax.
2.2 401 — Unauthorized
Authentication is required to access the requested file.
2.3 403 — Forbidden
The server denies access to the file. Check file permissions or directory protection settings in:
cPanel » Home » Advanced » Indexes
2.4 404 — Not Found
The requested file does not exist. This often occurs due to mistyped URLs or broken links.
3. Common 5xx Server Errors
These errors occur when the server cannot complete a valid request. They may originate from upstream servers in a multi‑server chain.
3.1 500 — Internal Server Error
A generic error caused by misconfigurations or application failures.
3.2 501 — Not Implemented
The server does not support the requested HTTP method.
3.3 502 — Bad Gateway
Often caused by proxy misconfiguration, ISP overload, or firewall issues. Clearing the client cache may help.
3.4 503 — Service Unavailable
The server is overloaded or undergoing maintenance.
3.5 504 — Gateway Timeout
A server did not receive a timely response from another server.
3.6 505 — HTTP Version Not Supported
The server does not support the HTTP protocol version used by the client.
3.7 506 — Variant Also Negotiates
Server configuration error.
3.8 507 — Insufficient Storage
The server lacks memory or resources to run the requested application.
3.9 509 — Bandwidth Limit Exceeded
The server has reached its bandwidth limit.
3.10 510 — Not Extended
The server does not support an extension required by the request.
4. InstaSite Configuration File
The InstaSite feature allows administrators to automatically generate a new website immediately after installing cPanel & WHM. This feature is experimental and available only to select hyperscalers.
The configuration file used by InstaSite is located at:
/var/cpanel/.create-website
This file temporarily stores account information in JSON format.
4.1 Required Parameters
| Parameter | Description | Example |
|---|---|---|
domain |
The new account’s domain name. | example.com |
username |
The new account’s username. | example |
password |
The new account’s password. | yourPassword |
4.2 Example File
{
"domain": "example.com",
"username": "example",
"password": "yourPassword"
}
Important:
Because this file contains a password, it must use 0600 permissions.
Conclusion
This guide provides a clear overview of common HTTP error codes and their quick fixes, along with a detailed explanation of the InstaSite configuration file used for automated website creation in cPanel & WHM. Understanding these tools helps administrators diagnose issues faster and streamline new account setup.
Written & researched by Dr. Shahin Siami