01 · Web fundamentals
Reading an
HTTP response.
A response has three useful parts: a status code, headers and a body. Looking at them separately makes many web problems easier to understand.
Start with the status
A successful page normally returns 200. A permanent redirect uses 301 or 308 and a Location header. A missing page should return 404, even when its error page has a friendly design.
Follow one redirect at a time
Check where a plain HTTP request goes before checking the final HTTPS page. A redirect should preserve the path and avoid a loop between hostnames or schemes.
Check resources too
An HTML page can load while its stylesheet is missing. The browser network panel shows status codes for images, fonts and scripts independently. A small site with local resources is particularly easy to inspect.
Keep the certificate check enabled
HTTPS verifies the requested hostname as well as the certificate chain. Disabling verification can help isolate a problem, but it does not establish that the connection is configured correctly.