Common HTTP Error status codes

Here is a list of common HTTP error response codes that you might encounter during your load test:

Client errors (400–499)

• 400 Bad Request – client-side input fails validation.
• 401 Unauthorized – not authorized request to access a resource, usually occurs when the user isn’t authenticated.
• 403 Forbidden – the user is authenticated, but it has not rights to access a resource.
• 404 Not Found – resource is not found.
• 429 Too Many Requests - the user has sent too many requests in a given amount of time ("rate limiting").

Server errors (500–599)

• 500 Internal server error – generic server error
• 502 Bad Gateway – an invalid response from an upstream server.
• 503 Service Unavailable – something unexpected happened on server side (server is overloaded with requests, server cannot handle load).