总结 1. 502没有收到相应,或者收到了但不及时? cannot get a response in time 540收到了无效的响应 received an invalid response from the upstream server, HTTP/1.1: Status Code Definitions https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10 10.5 Server Error 5xx Response…