Troubleshooting of HTTP errors: Difference between revisions

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== 400 Bad Request ==
== Troubleshooting HTTP Status Errors ==


Root cause of 400 Bad Request. HTTP Error 400. The request is badly formed.
=== 400 Bad Request ===
* "the server cannot or will not process the request due to something that is perceived to be a client error (for example, malformed request syntax, invalid request message framing, or deceptive request routing)"


Possible solution:
Root cause: The request itself is malformed. According to the spec, this means "the server cannot or will not process the request due to something perceived to be a client error" — such as invalid syntax, incorrect request message framing, or deceptive request routing.
* Modify the request headers


== 403 Forbidden Error ==
Possible fix:
* Review and correct the request headers
 
=== 403 Forbidden ===


See: [[How to fix the 403 forbidden error]]
See: [[How to fix the 403 forbidden error]]


== 404 File Not Found ==
=== 404 Not Found ===
Solution: Check if the accessed link is correct, see "404 Not Found | Possible solutions for pages not found"
 
Fix: Verify that the URL is correct. For more details, see
[[404 Not Found]], possible solutions for pages not found".
 
=== 405 Method Not Allowed ===
 
Fix: Confirm that the target resource supports the HTTP method you're using. For example, the endpoint may only accept POST requests while you're sending a GET request.
 
=== 414 Request-URI Too Large ===


== 405 Method Not Allowed Error ==
Fix: Switch from GET to POST so the data is sent in the request body instead of the URL.
Solution: Check if the accessed file or resource supports the HTTP protocol being used. For example, if the resource is restricted to POST requests but you're using GET.


== 414 Request-URI Too Large ==
=== 415 Unsupported Media Type ===
Solution: Change the request protocol to POST instead of GET


== 415 Unsupported Media Type ==
Fix: Explicitly declare the correct Content-Type or Content-Encoding in the request, or access the data directly. For instance, when calling a RESTful API, this error can often be resolved by adding the following header:


Solution: "Set the Content-Type or Content-Encoding in the request or direct access to the data." For example: When encountering this error with RESTful API, a possible solution is to add to the HTTP Headers:
<pre>
<pre>
Content-Type: application/json
Content-Type: application/json
</pre>
</pre>


== 429 Too Many Requests ==
=== 429 Too Many Requests ===
Root Cause:


* Accessing website resources or web service API too frequently
Root cause:
* The client is hitting the website or API more frequently than the service allows.


Solutions:
Fixes:
* '''Throttle your requests''': Add or increase a delay between requests based on your usage pattern and the service's limits (e.g., pause 1 second between calls).
* '''Check the API rate limits''': Consult the provider's documentation for limits such as Requests Per Minute (RPM) or Requests Per Day (RPD), and find out whether you can request a higher quota.
* '''Use exponential backoff''': Detect HTTP 429 responses in your
  application, then retry with progressively longer delays (e.g., 2s → 4s → 8s) until the request succeeds or a maximum retry count is reached.


* '''Adjust the delay time''' based on your usage patterns and the service's limits e.g. Increase the delay time between requests (e.g., add a 1-second pause between each request).
=== 502 Bad Gateway ===
* If accessing a web service API, Please refer to the documentation to understand the API access rate limits, such as:  (1) "Requests Per Minute" (RPM) – the maximum number of API requests you can make per minute, or (2) "Requests Per Day" (RPD) – the maximum number of API requests you can make per day. Check if you can request a higher quota limit from the service provider
* '''Implement exponential backoff retry mechanism''': Detect rate limit errors (HTTP 429) in your application. Increase the delay time with each failed retry (e.g., 2 seconds, 4 seconds, 8 seconds). Continue retrying until the request succeeds or maximum retry count is reached.


== 502 Bad Gateway ==
Cause:
Cause:
* Error occurs between network devices, users cannot directly handle it.
* A failure between upstream network devices/servers — not something the end user can fix directly.


Solutions:
Fixes:
* Bypass browser cache, refresh the page
* Hard-refresh the page to bypass the browser cache
* Try reconnecting after a while
* Wait a moment and try again


== Error 1020: Access Denied ==
=== Error 1020: Access Denied ===
* See link for understanding how to resolve Error 1020 Access Denied to get your website back online
* See the linked guide on resolving Error 1020 (Access Denied) to restore access to your website.


<pre>
== HTTP Cats or Dogs ==
Content-Type: application/json
</pre>


<div style="zoom: 0.4;">
https://http.cat/200.jpg
https://http.cat/200.jpg
From HTTP Cats
</div>
From [https://http.cat/ HTTP Cats]


Related websites:
Related websites:

Latest revision as of 16:49, 11 June 2026


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HTTP status code

🌐 Switch language: EN, 漢字


Troubleshooting HTTP Status Errors[edit]

400 Bad Request[edit]

Root cause: The request itself is malformed. According to the spec, this means "the server cannot or will not process the request due to something perceived to be a client error" — such as invalid syntax, incorrect request message framing, or deceptive request routing.

Possible fix:

  • Review and correct the request headers

403 Forbidden[edit]

See: How to fix the 403 forbidden error

404 Not Found[edit]

Fix: Verify that the URL is correct. For more details, see 404 Not Found, possible solutions for pages not found".

405 Method Not Allowed[edit]

Fix: Confirm that the target resource supports the HTTP method you're using. For example, the endpoint may only accept POST requests while you're sending a GET request.

414 Request-URI Too Large[edit]

Fix: Switch from GET to POST so the data is sent in the request body instead of the URL.

415 Unsupported Media Type[edit]

Fix: Explicitly declare the correct Content-Type or Content-Encoding in the request, or access the data directly. For instance, when calling a RESTful API, this error can often be resolved by adding the following header: 

Content-Type: application/json

429 Too Many Requests[edit]

Root cause:

  • The client is hitting the website or API more frequently than the service allows.

Fixes:

  • Throttle your requests: Add or increase a delay between requests based on your usage pattern and the service's limits (e.g., pause 1 second between calls).
  • Check the API rate limits: Consult the provider's documentation for limits such as Requests Per Minute (RPM) or Requests Per Day (RPD), and find out whether you can request a higher quota.
  • Use exponential backoff: Detect HTTP 429 responses in your
 application, then retry with progressively longer delays (e.g., 2s → 4s → 8s) until the request succeeds or a maximum retry count is reached.

502 Bad Gateway[edit]

Cause:

  • A failure between upstream network devices/servers — not something the end user can fix directly.

Fixes:

  • Hard-refresh the page to bypass the browser cache
  • Wait a moment and try again

Error 1020: Access Denied[edit]

  • See the linked guide on resolving Error 1020 (Access Denied) to restore access to your website.

HTTP Cats or Dogs[edit]

200.jpg

From HTTP Cats

Related websites:

Other possible root causes[edit]

  • CDN (Content delivery network)

Mock HTTP status error page tools[edit]

The testing sites that can return 500 and various other HTTP status codes on demand

Related pages[edit]

References[edit]

  1. ↑ httpresponse - Is there a website that returns 500 (and other) HTTP response codes for testing? - Stack Overflow


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