duongkimngoc I see you have a proxy_pass directive in your nginx config, that seems to use the HTTP server block for the website (?)
If the root for the HTTPS block is different from the HTTP block, then the sitemap location rule you added might actually be referencing the wrong url.
Could you maybe try placing that sitemap rule below the base location rule of the final server block ? You must have something like this somewhere:
location / {
try_files $uri $uri/ /index.php?$query_string;
}
And you can add the rule below so it looks something like this:
location / {
try_files $uri $uri/ /index.php?$query_string;
}
location = /sitemap.xml { try_files $uri $uri/ /index.php?$query_string; }
If you try that, remove the sitemap rule from its current location.
If that doesn't fix it, can you share the output of php flarum info ?
