Proxy behind Authelia and nginx Proxy Manager

[nousrfound]

I'm trying to place droppy behind Authelia and NPM but can't get it to work.

I followed the proxy guide and can get it to work without Authelia, but I don't know how to change it to also work with Authelia.

This is the template code I'm using for alll the other endpoints:

location /authelia {
    internal;
    set $upstream_authelia http://SERVERIP:9091/api/verify;
    proxy_pass_request_body off;
    proxy_pass $upstream_authelia;    
    proxy_set_header Content-Length "";

    # Timeout if the real server is dead
    proxy_next_upstream error timeout invalid_header http_500 http_502 http_503;
    client_body_buffer_size 128k;
    proxy_set_header Host $host;
    proxy_set_header X-Original-URL $scheme://$http_host$request_uri;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $remote_addr; 
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_set_header X-Forwarded-Host $http_host;
    proxy_set_header X-Forwarded-Uri $request_uri;
    proxy_set_header X-Forwarded-Ssl on;
    proxy_redirect  http://  $scheme://;
    proxy_http_version 1.1;
    proxy_set_header Connection "";
    proxy_cache_bypass $cookie_session;
    proxy_no_cache $cookie_session;
    proxy_buffers 4 32k;

    send_timeout 5m;
    proxy_read_timeout 240;
    proxy_send_timeout 240;
    proxy_connect_timeout 240;
}

    location / {
        set $upstream_CONTAINERNAME http://CONTAINERIP:CONTAINERPORT;
        proxy_pass $upstream_CONTAINERNAME;

        auth_request /authelia;
        auth_request_set $target_url $scheme://$http_host$request_uri;
        auth_request_set $user $upstream_http_remote_user;
        auth_request_set $groups $upstream_http_remote_groups;
        proxy_set_header Remote-User $user;
        proxy_set_header Remote-Groups $groups;
        error_page 401 =302 https://auth.YOURDOMAIN.com/?rd=$target_url;

        client_body_buffer_size 128k;

        proxy_next_upstream error timeout invalid_header http_500 http_502 http_503;

        send_timeout 5m;
        proxy_read_timeout 360;
        proxy_send_timeout 360;
        proxy_connect_timeout 360;

        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_set_header X-Forwarded-Host $http_host;
        proxy_set_header X-Forwarded-Uri $request_uri;
        proxy_set_header X-Forwarded-Ssl on;
        proxy_redirect  http://  $scheme://;
        proxy_http_version 1.1;
        proxy_set_header Connection "";
        proxy_cache_bypass $cookie_session;
        proxy_no_cache $cookie_session;
        proxy_buffers 64 256k;

        set_real_ip_from 192.168.1.0/16;
        real_ip_header X-Forwarded-For;
        real_ip_recursive on;

    }