I have a multilingual website built with Laravel and a multilingual WordPress blog (using WPML) in the “public” folder.

I’m trying to configure Nginx as a reverse proxy to serve the blog on specific subdirectories for each language (e.g., lamamita.it/blog, lamamita.es/blog).

I followed WPML’s instructions and configured Nginx as shown in the attached example.
However, when I access one of the blog subdirectories, I get a 502 error.

What I’ve tried:

• Nginx configuration: I’ve carefully checked the syntax and settings of the location /blog/ block.
• Permissions: I’ve ensured that file and directory permissions are correct.
• Nginx logs: I’ve checked the Nginx logs for any errors or warnings.

What I expect:

I would like to understand why I’m getting the 502 error and how to correct the Nginx configuration to make the reverse proxy work correctly.

Relevant code

location /blog/ {
  proxy_pass https://www.lamamita.it:443/blog/;
  proxy_set_header Host $host;
  proxy_set_header X-Real-IP $remote_addr;
  proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
  proxy_set_header X-Forwarded-Proto $scheme;
  proxy_buffer_size 16k;
  proxy_buffers 4 16k;
}

Additional information:

• Nginx version: 1.26.1
• PHP version: 8.0
• WordPress version: 6.6.2
• WPML version: 4.6.13
• Nginx error:

2024/09/18 15:01:53 [error] 1000837#1000837: *357241 upstream sent too big header while reading response header from upstream, client: 165.227.140.110, server: www.lamamita.es, request: “GET /blog/ HTTP/1.0”, upstream: “https://165.227.140.110:443/blog/”, host: “www.lamamita.es”

Question:

What other checks can I perform or what changes can I make to the Nginx configuration to fix this issue?