htpassword for nginx server on different ports

Question

I am trying to restrict users visiting a site via username and password. Doing it in apache is very simple. I am trying to do it in nginx for different ports, not just 80, but some other ports that the application hosted in the server will use. (It's a nodejs application, and currently it opens on port 3000)

What I have tried till now: Installed apache2 utility:

sudo apt-get install apache2-utils

create the htpassword user/password:

sudo htpasswd -c /etc/nginx/.htpasswd username

added the auth_user in etc/nginx/conf.d/default.conf:

. . .
listen      80;
server_name localhost;

location / {
        . . .
        auth_basic "Private Property";
        auth_basic_user_file /etc/nginx/.htpasswd;
}
. . .

reload nginx:

sudo service nginx reload

Now, when I open the site it's asking me for the username/password, but once I give them, it keeps asking me and doesn't let me log in.

I also want to add another port to be blocked via user/pass, like port 3000 ;

In etc/nginx/conf.d/default.conf I tried to add the ports the following ways:

. . .
listen      80;
listen      3000;
server_name localhost;

location / {
        . . .
        auth_basic "Private Property";
        auth_basic_user_file /etc/nginx/.htpasswd;
}
. . .

AND

server {
    listen        80;
    server_name  localhost;

    location / {
       ...
       auth_basic "Restricted Content";
       auth_basic_user_file .htpasswd;
    }
}

server {
    listen       3000 default_server;
    server_name  localhost;

    location / {
       ...
       auth_basic "Restricted Content";
       auth_basic_user_file .htpasswd;
    }
}

But it throws error, when nginx is reloaded.

So my question is:

1. How do I make the htpassword to work properly?

2. How do I make the htpassword to work properly for ports other than 80 and the application still runs properly?