nginx doesn't serve "/" path - nginx

Question

I have a domain example.com which is registered and working.
I am now trying redirect all requests to example.com and www.example.com to a specific port.
the default config in sites-enabled looks like this:
server{
listen 80;
listen [::]:80;
server_name example.com www.example.com;
location / {
return 301 https://example.com:8081/;
}
}
the above config does not work (when accessing example.com in the browser, i get infinite loading)
While when using this config, example.com/test works.
server{
listen 80;
listen [::]:80;
server_name example.com www.example.com;
location /test {
return 301 https://example.com:8081/;
}
}
nginx.conf
user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;
events {
worker_connections 768;
}
http {
sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 65;
types_hash_max_size 2048;
include /etc/nginx/mime.types;
default_type application/octet-stream;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
ssl_prefer_server_ciphers on;
access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;
gzip on;
include /etc/nginx/sites-enabled/*;
}