Troubleshooting of HTTP errors

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HTTP status code

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400 Bad Request

Root cause of 400 Bad Request. HTTP Error 400. The request is badly formed.

• "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:

• Modify the request headers

403 Forbidden Error

See: How to fix the 403 forbidden error

404 File Not Found

Solution: Check if the accessed link is correct, see "404 Not Found | Possible solutions for pages not found"

405 Method Not Allowed Error

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

Solution: Change the request protocol to POST instead of GET

415 Unsupported Media Type

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:

Content-Type: application/json

429 Too Many Requests

Root Cause:

• Accessing website resources or web service API too frequently

Solutions:

• 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).
• If accessing a web service API, read the documentation to understand the API's rate limits. 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:

• Error occurs between network devices, users cannot directly handle it.

Solutions:

• Bypass browser cache, refresh the page
• Try reconnecting after a while

Error 1020: Access Denied

• See link for understanding how to resolve Error 1020 Access Denied to get your website back online

Content-Type: application/json

From HTTP Cats

Related websites:

• HTTP Status Dogs

Other possible root causes

• CDN (Content delivery network)

Related pages

• Troubleshooting of curl errors
• Test connectivity for the web service

References

Troubleshooting of ...

• Troubleshooting of Excel errors

• PHP, cUrl, Python, selenium, HTTP status code errors

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• HTML/Javascript: Troubleshooting of javascript, XPath

• Software: Mediawiki, Docker, FTP problems, online conference software

• Test connectivity for the web service, Web Ping, Network problem, Web user behavior, Web scrape troubleshooting

Template

• Bug report template