If nginx -t succeeds but the browser response is unchanged, separate two questions: did the running process load the new file, and did the request select the server and location you edited? A syntax check answers neither by itself.
Changing only Host on the same port
A temporary Nginx 1.24.0 had a default server and a named.test server. Requests for other.test returned default-A; named.test returned named-A. The file was then edited from named-A to named-B and only nginx -t was run. Its exit code was 0, while the running server still returned named-A because no reload had occurred.
Compare address, port and Host selection with Nginx request processing. HTTPS also involves TLS virtual-host selection and SNI; an HTTP Host experiment does not validate certificate selection.
Match the running process to the tested file
Inspect the service start command and default paths shown by nginx -V. A process started with -c or -p must be checked with matching arguments. nginx -T expands includes but may expose tokens or internal addresses, so do not publish its complete output. Also distinguish CDN caching or a different origin behind the same domain.
For deployment, preserve the previous configuration, test it, inspect that service’s reload result and error log, and compare the same Host and path. If the response remains unchanged, revisit server selection and caching before restarting. This experiment does not establish a successful production reload.