Rewrite rules, for Zope, small problem with authentication user

Server NGINX
1

Hi, List

I would use Nginx with Zope, but with the following configuration I
can not authenticate the user (from Nginx), otherwise works properly.
Where am I doing wrong?

…
upstream database
{
postgres_server 172.16.65.1 dbname=dbname user=username
password=pwd;
}

upstream zope
{
    server 172.16.65.1:80;
}

server
{
    listen       80;
    server_name  www.myhostname.com;
    rewrite ^/(.*)

/VirtualHostBase/http/www.myhostname.com/www/VirtualHostRoot/$1 last;
index index.htm index.html index_html;

    location =/auth
    {
        internal;
        more_set_headers -s 401 'WWW-Authenticate: Basic

realm="$auth_user"’;
postgres_escape $user $remote_user;
postgres_escape $pass $remote_passwd;
postgres_pass database;
postgres_query “SELECT user FROM usertable WHERE
user=$user AND pwd=crypt($pass, pwd) $private”;
postgres_rewrite no_rows 401;
postgres_output none;
}

    # For registered users in DB
    location /news/
    {
        set $auth_user "News";
        set $private "and reserve ='S'";
        auth_request  /auth;
    }

    location /
    {
        proxy_set_header  X-Real-IP  $remote_addr;
        proxy_pass http://zope;
    }

    error_page  405              /error/405.htm;
    error_page  404              /error/404.htm;
    error_page  403              /error/403.htm;

    # redirect server error pages to the static page /50x.html
    #
    error_page   500 502 503 504  /error/50x.html;
}

…

Thanks in advance
Giuseppe