HTTP status code 0 – Error Domain=NSURLErrorDomain?
There is no HTTP status code 0. What you see is a 0 returned by the API/library that you are using. You will have to check the documentation for that.
http-status-codes
How do I resolve a HTTP 414 “Request URI too long” error?
Under Apache, the limit is a configurable value, LimitRequestLine. Change this value to something larger than its default of 8190 if you want to support a longer request URI. The value is in /etc/apache2/apache2.conf. If not, add a new line (LimitRequestLine 10000) under AccessFileName .htaccess. However, note that if you’re actually running into this limit, you are probably … Read more
403 Forbidden vs 401 Unauthorized HTTP responses
A clear explanation from Daniel Irvine: There’s a problem with 401 Unauthorized, the HTTP status code for authentication errors. And that’s just it: it’s for authentication, not authorization. Receiving a 401 response is the server telling you, “you aren’t authenticated–either not authenticated at all or authenticated incorrectly–but please reauthenticate and try again.” To help you … Read more
Should a 502 HTTP status code be used if a proxy receives no response at all?
Yes. Empty or incomplete headers or response body typically caused by broken connections or server side crash can cause 502 errors if accessed via a gateway or proxy. For more information about the network errors