404 Error | WordPress Multisite + nginx + php-fpm

I am getting 404 Errors on my WordPress Multisite installation. It is a path based multisite (/en/, /es/ etc.). It is under nginx + php-fpm. I have properly configured the wp-config.php file with the following lines:

define( 'WP_ALLOW_MULTISITE', true );
define('MULTISITE', true);
define('SUBDOMAIN_INSTALL', false);
define('DOMAIN_CURRENT_SITE', 'website.com');
define('PATH_CURRENT_SITE', '/');
define('SITE_ID_CURRENT_SITE', 1);
define('BLOG_ID_CURRENT_SITE', 1);
define( 'WP_DEFAULT_THEME', 'theme' );

And I have added the following rules to the nginx vhost server block:

if (!-e $request_filename) {
rewrite /wp-admin$ $scheme://$host$uri/ permanent;
rewrite ^(/[^/]+)?(/wp-.*) $2 last;
rewrite ^(/[^/]+)?(/.*\.php) $2 last;
}

The curious thing is that this is a site being migrated from one server to another. On the first server, it worked, on the second server, it does not work.

I am guessing, it is something related with the nginx config. Here is the full nginx .stpl file: https://gist.github.com/alexgarciab/cad0049697705e2bf94e75e86ec2f144

Anyone can help me out? Thanks