nginx ubuntu user password

I have a nodejs backend hosted on AWS EC2 Ubuntu 20.04 instances.

When i ssh into my server, everything is working accordingly. Today i tried configuring nginx, so i created website.com files inside sites-available .

website.com

server {
        listen 80;
        listen [::]:80;

         root /home/ubuntu/apps/yelp-app/client/build;

        # Add index.php to the list if you are using PHP
        index index.html index.htm index.nginx-debian.html;

        server_name api.website.com www.api.website.com;

        location / {
                try_files $uri /index.html;
        }

         location /api {
            proxy_pass http://localhost:3001;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection 'upgrade';
            proxy_set_header Host $host;
            proxy_cache_bypass $http_upgrade;
        }

}

After saving that file, i ran the following command:

sudo ln -s /etc/nginx/sites-available/website.com /etc/nginx/sites-enabled/

From the docs, in order to enable the new site i need to restart nginx using the following:

systemctl restart nginx

Unfortunately, it keeps asking for the ubuntu user password which i did not ever set.

Can someone help me out?

When i run journalctl -xe -u nginx this is what i get:

-- Subject: A start job for unit nginx.service has begun execution
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
-- 
-- A start job for unit nginx.service has begun execution.
-- 
-- The job identifier is 23231.
Jan 11 12:44:45 ip-172-31-40-105 nginx[164236]: nginx: [emerg] a duplicate default server for 0.0.0.0:80 in >
Jan 11 12:44:45 ip-172-31-40-105 nginx[164236]: nginx: configuration file /etc/nginx/nginx.conf test failed
Jan 11 12:44:45 ip-172-31-40-105 systemd[1]: nginx.service: Control process exited, code=exited, status=1/FA>
-- Subject: Unit process exited
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
-- 
-- An ExecStartPre= process belonging to unit nginx.service has exited.
-- 
-- The process' exit code is 'exited' and its exit status is 1.
Jan 11 12:44:45 ip-172-31-40-105 systemd[1]: nginx.service: Failed with result 'exit-code'.
-- Subject: Unit failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
-- 
-- The unit nginx.service has entered the 'failed' state with result 'exit-code'.
Jan 11 12:44:45 ip-172-31-40-105 systemd[1]: Failed to start A high performance web server and a reverse pro>
-- Subject: A start job for unit nginx.service has failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
-- 
-- A start job for unit nginx.service has finished with a failure.
-- 
-- The job identifier is 23231 and the job result is failed.