error="failed to parse content of Authorization header: invalid scheme: the scheme is missing"

[jiriteach]

Hi - I have Authelia working well with NGINX for several sites but I am trying to setup a proxy host for NGINX GUI - https://nginxui.com/.

Works fine without Authelia but when I use a similar working setup - I get this error -

time="2024-07-22T19:11:56+12:00" level=error msg="Error occurred while attempting to authenticate a request" error="failed to parse content of Authorization header: invalid scheme: the scheme is missing" method=GET path=/api/authz/auth-request remote_ip=192.168.xxx.xxx

Use stock as per recommendation Authelia snippets and site conf is as follows.
Any ideas on how to fix this? All my other sites are working fine. I have seen another post where there was a fix done - I'm running the latest version of Authelia and still seeing this.

Thanks

server {

    set $forward_scheme http;
    
    ## - UPDATE SERVER & PORT
    ## ----------------------
    set $server         "192.168.xx.xx";
    set $port           9000;
    ## ----------------------
  
    listen 443 ssl;
    listen [::]:443 ssl;
    
    ## - UPDATE HOSTNAME
    ## -----------------
    server_name xxx.xxx.xxx.nz;
    ## -----------------
    
    ssl_certificate /etc/nginx/ssl/*.xxx.xxx.xxx.xxx.nz_2048/fullchain.cer;
    ssl_certificate_key /etc/nginx/ssl/*.xxx.xxx.nz_xxx.xxx.nz_2048/private.key;
    
    ## - WEBSOCKET SUPPORT
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $http_connection;
    proxy_http_version 1.1;
    
    ## - AUTHELIA SUPPORT
    include snippets/authelia-location.conf; 
        
    location / {
    
        ## - AUTHELIA SUPPORT
        include snippets/proxy.conf; 
        include snippets/authelia-authrequest.conf;
    
        ## - WEBSOCKET SUPPORT
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $http_connection;
        proxy_http_version 1.1;    
        
        ## - OTHER REQUIRED HEADERS
        add_header       X-Served-By $host;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-Scheme $scheme;
        proxy_set_header X-Forwarded-Proto  $scheme;
        proxy_set_header X-Forwarded-For    $proxy_add_x_forwarded_for;
        proxy_set_header X-Real-IP          $remote_addr;
        proxy_pass       $forward_scheme://$server:$port$request_uri;
        
    }
}

[jiriteach]

Fixed this thanks to @james-d-elliott. Needed to use AuthRequest in my case given im using NGINX.
So -

server:
  endpoints:
    authz:
      auth-request:
        implementation: 'AuthRequest'