Server

HTTP Status Code 511 refers to Network Authentication Required. This status code indicates that the client needs to authenticate to gain network access. It's often used by proxy servers to signal that the client must provide authentication credentials before it can access the requested resource.

HTTP Status Code 510 refers to Not Extended. It indicates that further extensions to the request are required for the server to fulfill it. This status code is used when the server requires additional information or extensions that were not provided in the initial request.

HTTP Status Code 508 refers to Loop Detected. It indicates that the server has encountered an infinite loop while processing a request, which prevents it from completing the operation. This status code is used when a server recognizes that a request could not be fulfilled due to a cycle in a resource's configuration, often arising from a misconfiguration in a server-side script or during the handling of a request that involves multiple resources.

HTTP Status Code 507 indicates Insufficient Storage, which means the server is unable to store the representation needed to complete the request. This status code is primarily used in WebDAV applications, where the server might run out of storage space to fulfill the request. When a server responds with HTTP Status Code 507, it signals that the server cannot allocate enough space to complete the operation, such as when creating or modifying resources.

HTTP Status Code 506 indicates Variant Also Negotiates, which occurs when the server has an internal configuration error related to content negotiation. Essentially, this status code is returned when the server cannot complete the request because it cannot determine the proper variant of the resource requested due to a conflict in its settings. This can happen in systems using content negotiation techniques, where different representations of the resource are available, but the server is unable to resolve the request based on the client’s specifications.

HTTP Status Code 505 signifies HTTP Version Not Supported, which means that the server does not support the HTTP protocol version that was used in the request. This status code indicates that the client has requested an HTTP version that the server cannot handle, and thus it cannot fulfill the request. When a server responds with HTTP Status Code 505, it suggests that the client should consider using a different version of HTTP that is compatible with the server.

HTTP Status Code 504 indicates Gateway Timeout, which occurs when a server acting as a gateway or proxy does not receive a timely response from an upstream server it needs to access in order to complete the request. This status code tells the client that while the gateway was able to connect to the upstream server, the response took too long, leading to a timeout situation. When a server returns HTTP Status Code 504, it suggests that there might be issues with the upstream server or network connectivity.

HTTP Status Code 503 signifies Service Unavailable, which means that the server is temporarily unable to handle the request, usually due to maintenance or overloading. When a server returns HTTP Status Code 503, it indicates that the server is currently unable to process incoming requests but may become available again after some time. This response is often a temporary state, and the client might attempt to retry the request after waiting for a specified period.

HTTP Status Code 502 indicates Bad Gateway, meaning that a server acting as a gateway or proxy received an invalid response from an upstream server. When a server encounters HTTP Status Code 502, it suggests that it was unable to get a valid response while trying to fulfill a request that involves communicating with another server. This might occur when the upstream server is down, misconfigured, or not responding properly, leading to the gateway server being unable to relay a valid response back to the client.

HTTP Status Code 501 signifies Not Implemented, indicating that the server does not support the functionality required to fulfill the request. When a server responds with HTTP Status Code 501, it means that the server either does not recognize the request method or lacks the capability to fulfill the request. This status code often appears when a client sends a request using a method that the server cannot process, such as PUT or DELETE, which might not be implemented on that server.