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. In such cases, the client may want to retry the request later or contact the server administrator for further investigation into the issue.