Traefik 3.x with Passbolt HTTP setup giving CORS error

I have a CORS issue using Traefik 3.02 and I have been unable to fix despite trying. I have deliberately kept everything simple.

I am NOT using Docker or HTTPS/TLS, everything installed in a Debian 12 VM with just HTTP Passbolt installed, and Traefik on a different VM. I can access Passbolt using the IPv4 with no issues, but as soon as I use the domain name, which goes through Traefik, I get the bellow CORS error. I am uncertain if something requires changing on the Passbolt side. I have provided the NGiNX Passbolt for reference .

Uncertain why I cannot bypass the CORS error with the below Traefik settings:

        accessControlAllowMethods: "*"
        accessControlAllowOriginList: "*"
        accessControlMaxAge: 100
        addVaryHeader: true
        contentSecurityPolicy: "default-src 'self' *;"

#  Passbolt.conf - Nginx configuration file to run the Passbolt software.

server {

  listen 80;
  listen [::]:80;

  # Managed by Passbolt
  server_name passbolt.domain-name.tld;

  client_body_buffer_size     100K;
  client_header_buffer_size   1K;
  client_max_body_size        5M;

  client_body_timeout   10;
  client_header_timeout 10;
  keepalive_timeout     5 5;
  send_timeout          10;

  root /usr/share/php/passbolt/webroot;
  index index.php;
  error_log /var/log/nginx/passbolt-error.log info;
  access_log /var/log/nginx/passbolt-access.log;

  # Managed by Passbolt
  # include __PASSBOLT_SSL__

  location / {
    try_files $uri $uri/ /index.php?$args;

  location ~ \.php$ {
    try_files                $uri =404;
    include                  fastcgi_params;
    fastcgi_pass             unix:/run/php/php8.2-fpm.sock;
    fastcgi_index            index.php;
    fastcgi_intercept_errors on;
    fastcgi_split_path_info  ^(.+\.php)(.+)$;
    fastcgi_param            SCRIPT_FILENAME $document_root$fastcgi_script_name;
    fastcgi_param            SERVER_NAME $http_host;
    fastcgi_param PHP_VALUE  "upload_max_filesize=5M \n post_max_size=5M";


Would appreciate it if someone can assist me understand and resolve the issue.