HTTP Error: How to Fix HTTP Errors

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Yesterday I received an error message while trying to access a website, and the infamous http status code that appeared on the screen forced me to stop.

I thought: “How many of us really know what these codes mean when we try to access a web page? And above all, how can we fix them?”

So I decided to dig deeper into the topic of status code http and, in particular, http errors, going beyond the simple list of numbers and explaining the most common causes and possible solutions — even for those managing WordPress sites without much technical experience.

In this article, I’ll guide you through the main http status codes, from the well-known http error 404 to the more complex ones such as http error 502 or http error 503, providing a clear and practical approach to handle them.

In addition, for each http error, I provide a dedicated page with more details.

Table of Contents

• What Are HTTP Status Codes?
• Comparative Table of the Main HTTP Error Codes
• HTTP Error 400 – Bad Request
• HTTP Error 401 – Unauthorized
• HTTP Error 403 – Forbidden
• HTTP Error 404 – Not Found
• HTTP Error 408 – Request Timeout
• HTTP Error 429 – Too Many Requests
• HTTP Error 500 – Internal Server Error
• HTTP Error 502 – Bad Gateway
• HTTP Error 503 – Service Unavailable
• HTTP Error 504 – Gateway Timeout
• Final Thoughts
• FAQ

What Are HTTP Status Codes?

HTTP status codes are the responses that a web server sends to a browser or client when a request is made. In other words, every time we try to open a page, the server replies with a numerical code that tells us whether the request was completed successfully or if a problem occurred.

These status codes http are standardized by web protocols and recognized by search engines, which also use them to determine whether content is available or not.

The main families are:

• 1xx: informational
• 2xx: success (e.g., the famous 200 OK)
• 3xx: redirections
• 4xx: client-side errors
• 5xx: server-side errors

In this article, we’ll focus on the most common http error codes from the 4xx and 5xx families.

Comparative Table of the Main HTTP Error Codes

Code	Name	Meaning	When It Happens	Typical Fix
400	Bad Request	Malformed or incomplete request	Wrong URL, invalid parameters	Check the address or submitted data
401	Unauthorized	Access denied, authentication needed	Protected page without login	Log in with valid credentials
403	Forbidden	Access denied even if authenticated	Insufficient permissions, restrictions	Requires permission from the site
404	Not Found	Resource not found	Removed page, wrong URL	Check spelling or look for updated page
408	Request Timeout	Server did not receive request in time	Slow or unstable connection	Reload the page, check connection
429	Too Many Requests	Too many requests in short time	Anti-abuse limits, refresh or bots	Wait, change IP, reduce requests
500	Internal Server Error	Generic server error	Internal malfunction of the site	Wait for the admin to fix it
502	Bad Gateway	Invalid response from proxy server	Issues between intermediate servers	Try again later
503	Service Unavailable	Server temporarily unavailable	Overload, maintenance	Wait and retry
504	Gateway Timeout	Upstream server did not respond in time	Network issues between servers	Try again later

In short:

• 404 = the page doesn’t exist.
• 403 = it exists, but you can’t see it.
• 429 = it exists, but you’re temporarily blocked.
• 500+ = server-side problem.

HTTP Error 400 – Bad Request

Http error 400 means the request sent by the browser is invalid or malformed. It often happens due to misconfigurations, misspelled URLs, or invalid data.

How to fix http error 400:

• Refresh the page and check that the URL is correct.
• Clear the cache and browser cookies.
• On WordPress sites, check for conflicting plugins.

HTTP Error 401 – Unauthorized

Http error 401 appears when trying to access a protected resource without valid credentials.

How to fix http error 401:

• Enter the correct username and password.
• Check server configuration files.
• If you manage the site, ensure authentication is set properly.

HTTP Error 403 – Forbidden

Http error 403 indicates that the server understood the request but denies access.

How to fix http error 403:

• Review configuration files (e.g., .htaccess).
• Check file and folder permissions.
• On WordPress, temporarily disable security plugins that may block access.

HTTP Error 404 – Not Found

The most famous one: http error 404 means the requested page no longer exists or is unreachable. It’s also a negative signal for search engines.

How to fix http error 404:

• Refresh the page and check the link.
• Ensure there is an updated content index.
• Implement proper redirects if the page was moved.

HTTP Error 408 – Request Timeout

An http error 408 happens when the server takes too long processing the request, causing the connection to time out.

How to fix http error 408:

• Reload the page or try again later.
• Check internet connection stability.
• Admins should check for server overload.

HTTP Error 429 – Too Many Requests

Http error 429 occurs when a user or bot sends too many requests in a short period.

How to fix http error 429:

• Wait a few minutes before trying again.
• Website admins should configure a more flexible rate limit.
• On WordPress, check if security plugins are blocking access.

HTTP Error 500 – Internal Server Error

A http error 500 is a generic server-side error, often caused by misconfigurations or faulty configuration files.

How to fix http error 500:

• Check server logs.
• Restore any corrupted .htaccess files.
• Temporarily disable plugins to see if the site recovers.

HTTP Error 502 – Bad Gateway

Http error 502 means a server received an invalid response from another server, common with proxies or CDNs.

How to fix http error 502:

• Clear the cache and reload the page.
• Contact your hosting provider.
• Review reverse proxy or firewall configurations.

HTTP Error 503 – Service Unavailable

Http error 503 occurs when the server is unavailable, often due to maintenance or server overload.

How to fix http error 503:

• Wait a few minutes and try again.
• Optimize server processes.
• On WordPress, check if a plugin caused the crash.

HTTP Error 504 – Gateway Timeout

An http error 504 happens when the server doesn’t receive a timely response from another upstream server.

How to fix http error 504:

• Reload the page or try another connection.
• Verify proxy configuration.
• Contact your hosting provider if the issue persists.

Final Thoughts

HTTP status codes shouldn’t scare us: behind each number is a precise explanation and, in most cases, a simple solution. The key is understanding whether the issue comes from the client side or from server-side problems, and acting accordingly.

If you manage a website and often face these issues, remember that Dopstart offers a free initial consultation to help you diagnose and fix these errors, guiding you through the entire optimization and technical management process.

FAQ

1. What are http status codes?
They are numerical codes that the server sends to the browser to indicate the status of a request.

2. What’s the difference between 4xx and 5xx errors?
4xx indicate client-side problems, while 5xx indicate server-side issues.

3. How to fix http error 400?
Check the URL, clear cache, and review WordPress plugins.

4. How to fix http error 401?
Make sure credentials are correct and review configuration files.

5. How to fix http error 403?
Check permissions, .htaccess, and security plugins.

6. How to fix http error 404?
Refresh the page, check links, and set up proper redirects.

7. How to fix http error 408?
Reload the page and check your internet connection.

8. How to fix http error 429?
Reduce requests, wait, and review WordPress security plugins.

9. How to fix http error 500?
Check server logs and review configuration errors.

10. How to fix http errors 503 and 504?
For 503, wait until the server is available. For 504, check proxy settings.